Systems and methods for IIP address sharing across cores in a multi-core system

ABSTRACT

In a multi-core system, multiple packet engines across corresponding cores may be working concurrently processing data packets from data flows of SSL VPN sessions. For example, a first core may establish a SSL VPN session with a client. Any one of the other cores, such as a second core, may received packets related to the session owned by the first core. Embodiments of the systems and method described below provide management of IIP addresses for the multi-core/multi-packet engine approach to providing SSL VPN service. In some embodiments, the approach to managing IIP addresses is to have one packet engine on a core act as a master or controller of the IIPs for the remaining packet engines and cores. The packet engines/cores use a protocol for communications regarding IIP management.

RELATED APPLICATION

The present application claims the benefit if and is a continuation ofU.S. patent application Ser. No. 12/851,438 entitled “SYSTEMS ANDMETHODS FOR IP ADDRESS SHARING ACROSS CORES IN A MULTI-CORE SYSTEM” andfiled on Aug. 5, 2010, which is incorporated herein by reference in itsentirety for all purposes.

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

FIELD OF THE INVENTION

The present application generally relates to data communicationnetworks. In particular, the present application relates to systems andmethods for assigning, managing, and providing by a multi-core systemIntranet Internet Protocol addresses for SSL VPN users.

BACKGROUND OF THE INVENTION

A typical computer system uses a single internet protocol (IP) addressassigned to the computer system. Any user session or program on thecomputer will use the IP address of the computer for networkcommunications on a TCP/IP network. Communications over the network toand from the computer, for example between a client and a server, usethe computer's IP address as part of the network communications of thecomputer. In a virtual private network environment, a remote user mayestablish a virtual private network connection from a client to a secondnetwork, such as via an SSL VPN connection from a client on a publicnetwork to a server on a private network. On the second network, asecond IP address is used for communications between the client and theserver.

A user of the virtual private network may log in via the same computingdevice or roam between computing devices. For each login session, adifferent second IP address may be used for virtual private networkcommunications. Also, for each computing device of the user, a differentsecond IP address may be used for virtual private networkcommunications. As such, the user and/or computing device of the usermay be associated with different IP addresses on the virtual privatenetwork at various times. In some cases, the user may have multiplevirtual private network sessions concurrently, and thus, multiple IPaddresses on the private network. Identifying, tracking or managing thevirtual private network addresses of remote users is challenging, andmay be compounded in an environment with a multitude of remote virtualprivate network users. Thus, it is desirable to provide systems andmethods to more efficiently manage and assign IP addresses for users ofa virtual private network. It is also desirable to provide systems andmethods to identify the virtual private network address assigned to auser of a virtual private network.

In one case, an application is designed and constructed to operate usingthe local internet protocol address of the client. When the user isconnected via a virtual private network connection to a second network,the application may have issues communicating over the connection to theprivate network. For instance, the application may only be aware of theIP address assigned to the computer. Since it is not aware of any of thesecond IP addresses associated with the user or computer on the virtualprivate network, the application may not be able to communicate over thevirtual private network connection. Thus, it is desirable to providesystems and methods to allow an application to communicate over thevirtual private network connection using virtual private network IPaddresses.

BRIEF SUMMARY OF THE INVENTION

In a multi-core system, multiple packet engines across correspondingcores may be working concurrently processing data packets from dataflows of SSL VPN sessions. For example, a first core may establish a SSLVPN session with a client. Any one of the other cores, such as a secondcore, may receive packets related to the session owned by the firstcore. Embodiments of the systems and method described below providemanagement of intranet internet protocol (IIP) addresses for themulti-core/multi-packet engine approach to providing SSL VPN service. Insome embodiments, the approach to managing IIP addresses is to have onepacket engine on a core act as a master or controller of the IIPs forthe remaining packet engines and cores. The packet engines/cores use aprotocol for communications regarding IIP management.

In one aspect, the present invention relates to a method for managingintranet internet protocol (IIP) addresses via a multi-core deviceintermediary to a server and a plurality of clients. The methodcomprises designating, by a device intermediary to a plurality ofclients and a server, a first core of a plurality of cores of the deviceas a controller core for managing intranet internet protocol (IIP)addresses assigned by the device to sessions of the plurality ofclients; receiving, by a second core of the plurality of cores from athird core of the plurality of cores, a communication regarding asession established by the second core; and communicating, by the secondcore to the controller core, a request for an IIP address for thesession. The method further comprises communicating, by the second coreto the third core, the IIP address allocated by the controller core tothe session.

In some embodiments, the method further comprises selecting, uponstartup of the device, one core of the plurality of cores as thecontroller core and communicating the selection to each non-selectedcore of the plurality of cores. In other embodiments, the third core mayreceive an event from the client via the session. The event may comprisea set client message from the client. The third core may furthercommunicate to the second core information about the event. In otherembodiments, the third core may determine that the third core is not anowner of the session. In one embodiment, the third core may determinefrom a session identifier of the session that the second core is theowner of the session. In some embodiment, the second core maycommunicate to the controller core information about the session. Inother embodiments, the controller core may assign to the session the IIPaddress comprising an intranet protocol address of a first networkassigned to the client operating on a second network and accessing theserver of the first network via the device. In some embodiments, one ofthe second core or the controller core may communicate to other cores ofthe plurality of cores the allocation of the IIP address to the session.The plurality of cores may accept, responsive to the allocation of theIIP address to the session, packets from the client for the IIP address.

In other aspects, the present invention relates to a system for managingintranet internet protocol addresses via a multi-core deviceintermediary to a server and a plurality of clients. The systemcomprises a device intermediary to a plurality of clients and a server.A first core of a plurality of cores of the device is designated as acontroller core for managing intranet internet protocol (IIP) addressesassigned by the device to sessions of the plurality of clients. A secondcore of the plurality of cores receives from a third core of theplurality of cores a communication regarding a session established bythe second core and communicates to the controller core a request for anIIP address for the session. The second core communicates to the thirdcore the IIP address allocated by the controller core to the session.

In some embodiments, upon startup, the device selects one core of theplurality of cores as the controller core and communicates the selectionto each non-selected core of the plurality of cores. In one embodiment,the third core receives an event from the client via the session. Inother embodiments, the event comprises a set client message from theclient. In one embodiment, the third core may communicate to the secondcore information about the event. In some other embodiments, the thirdcore may determine that the third core is not an owner of the session.In one embodiment, the third core determines from a session identifierof the session that the second core is the owner of the session. Inother embodiments, the second core communicates to the controller coreinformation about the session. In another embodiment, the controllercore allocates to the session, the IIP address comprising an intranetprotocol address of a first network assigned to the client operating ona second network and accessing the server of the first network via thedevice. In certain embodiments, one of the second core or the controllercore communicates to other cores of the plurality of cores theallocation of the IIP address to the session. In other embodiments, theplurality of cores, responsive to the allocation of the IIP address tothe session, may accept packets from the client for the IIP address.

The details of various embodiments of the invention are set forth in theaccompanying drawings and the description below.

BRIEF DESCRIPTION OF THE FIGURES

The foregoing and other objects, aspects, features, and advantages ofthe invention will become more apparent and better understood byreferring to the following description taken in conjunction with theaccompanying drawings, in which:

FIG. 1A is a block diagram of an embodiment of a network environment fora client to access a server via an appliance;

FIG. 1B is a block diagram of an embodiment of an environment fordelivering a computing environment from a server to a client via anappliance;

FIG. 1C is a block diagram of another embodiment of an environment fordelivering a computing environment from a server to a client via anappliance;

FIG. 1D is a block diagram of another embodiment of an environment fordelivering a computing environment from a server to a client via anappliance;

FIGS. 1E-1H are block diagrams of embodiments of a computing device;

FIG. 2A is a block diagram of an embodiment of an appliance forprocessing communications between a client and a server;

FIG. 2B is a block diagram of another embodiment of an appliance foroptimizing, accelerating, load-balancing and routing communicationsbetween a client and a server;

FIG. 3 is a block diagram of an embodiment of a client for communicatingwith a server via the appliance;

FIG. 4A is a block diagram of an embodiment of a virtualizationenvironment;

FIG. 4B is a block diagram of another embodiment of a virtualizationenvironment;

FIG. 4C is a block diagram of an embodiment of a virtualized appliance;

FIG. 5A are block diagrams of embodiments of approaches to implementingparallelism in a multi-core system;

FIG. 5B is a block diagram of an embodiment of a system utilizing amulti-core system;

FIG. 5C is a block diagram of another embodiment of an aspect of amulti-core system; and

FIG. 6 is a block diagram of an embodiment of an appliance and clientproviding an Intranet Internet Protocol (IIP) environment;

FIG. 7 is a flow diagram depicting steps of an embodiment of a methodfor practicing a technique for assigning an IIP address to a user;

FIG. 8 is a flow diagram depicting steps of an embodiment of a methodfor providing the IIP address assigned to the user to an application ona client; and

FIG. 9 is a flow diagram depicting steps of an embodiment of a methodfor querying the IIP address assigned to a user.

FIG. 10A is a block diagram of an embodiment of a multi-core systemproviding an Intranet Internet Protocol (IIP) environment; and

FIG. 10B is a flow diagram depicting steps of an embodiment of a methodfor multi-core system to provide IIP addresses.

The features and advantages of the present invention will become moreapparent from the detailed description set forth below when taken inconjunction with the drawings, in which like reference charactersidentify corresponding elements throughout. In the drawings, likereference numbers generally indicate identical, functionally similar,and/or structurally similar elements.

DETAILED DESCRIPTION OF THE INVENTION

For purposes of reading the description of the various embodimentsbelow, the following descriptions of the sections of the specificationand their respective contents may be helpful:

-   -   Section A describes a network environment and computing        environment which may be useful for practicing embodiments        described herein;    -   Section B describes embodiments of systems and methods for        delivering a computing environment to a remote user;    -   Section C describes embodiments of systems and methods for        accelerating communications between a client and a server;    -   Section D describes embodiments of systems and methods for        virtualizing an application delivery controller;    -   Section E describes embodiments of systems and methods for        providing a multi-core architecture and environment;    -   Section F describes embodiments of systems and methods for        providing an IIP addressing environment; and    -   Section F describes embodiments of systems and methods for        providing an IIP addressing environment by a multi-core system.        A. Network and Computing Environment

Prior to discussing the specifics of embodiments of the systems andmethods of an appliance and/or client, it may be helpful to discuss thenetwork and computing environments in which such embodiments may bedeployed. Referring now to FIG. 1A, an embodiment of a networkenvironment is depicted. In brief overview, the network environmentcomprises one or more clients 102 a-102 n (also generally referred to aslocal machine(s) 102, or client(s) 102) in communication with one ormore servers 106 a-106 n (also generally referred to as server(s) 106,or remote machine(s) 106) via one or more networks 104, 104′ (generallyreferred to as network 104). In some embodiments, a client 102communicates with a server 106 via an appliance 200.

Although FIG. 1A shows a network 104 and a network 104′ between theclients 102 and the servers 106, the clients 102 and the servers 106 maybe on the same network 104. The networks 104 and 104′ can be the sametype of network or different types of networks. The network 104 and/orthe network 104′ can be a local-area network (LAN), such as a companyIntranet, a metropolitan area network (MAN), or a wide area network(WAN), such as the Internet or the World Wide Web. In one embodiment,network 104′ may be a private network and network 104 may be a publicnetwork. In some embodiments, network 104 may be a private network andnetwork 104′ a public network. In another embodiment, networks 104 and104′ may both be private networks. In some embodiments, clients 102 maybe located at a branch office of a corporate enterprise communicatingvia a WAN connection over the network 104 to the servers 106 located ata corporate data center.

The network 104 and/or 104′ be any type and/or form of network and mayinclude any of the following: a point to point network, a broadcastnetwork, a wide area network, a local area network, a telecommunicationsnetwork, a data communication network, a computer network, an ATM(Asynchronous Transfer Mode) network, a SONET (Synchronous OpticalNetwork) network, a SDH (Synchronous Digital Hierarchy) network, awireless network and a wireline network. In some embodiments, thenetwork 104 may comprise a wireless link, such as an infrared channel orsatellite band. The topology of the network 104 and/or 104′ may be abus, star, or ring network topology. The network 104 and/or 104′ andnetwork topology may be of any such network or network topology as knownto those ordinarily skilled in the art capable of supporting theoperations described herein.

As shown in FIG. 1A, the appliance 200, which also may be referred to asan interface unit 200 or gateway 200, is shown between the networks 104and 104′. In some embodiments, the appliance 200 may be located onnetwork 104. For example, a branch office of a corporate enterprise maydeploy an appliance 200 at the branch office. In other embodiments, theappliance 200 may be located on network 104′. For example, an appliance200 may be located at a corporate data center. In yet anotherembodiment, a plurality of appliances 200 may be deployed on network104. In some embodiments, a plurality of appliances 200 may be deployedon network 104′. In one embodiment, a first appliance 200 communicateswith a second appliance 200′. In other embodiments, the appliance 200could be a part of any client 102 or server 106 on the same or differentnetwork 104,104′ as the client 102. One or more appliances 200 may belocated at any point in the network or network communications pathbetween a client 102 and a server 106.

In some embodiments, the appliance 200 comprises any of the networkdevices manufactured by Citrix Systems, Inc. of Ft. Lauderdale Fla.,referred to as Citrix NetScaler devices. In other embodiments, theappliance 200 includes any of the product embodiments referred to asWebAccelerator and BigIP manufactured by F5 Networks, Inc. of Seattle,Wash. In another embodiment, the appliance 205 includes any of the DXacceleration device platforms and/or the SSL VPN series of devices, suchas SA 700, SA 2000, SA 4000, and SA 6000 devices manufactured by JuniperNetworks, Inc. of Sunnyvale, Calif. In yet another embodiment, theappliance 200 includes any application acceleration and/or securityrelated appliances and/or software manufactured by Cisco Systems, Inc.of San Jose, Calif., such as the Cisco ACE Application Control EngineModule service software and network modules, and Cisco AVS SeriesApplication Velocity System.

In one embodiment, the system may include multiple, logically-groupedservers 106. In these embodiments, the logical group of servers may bereferred to as a server farm 38. In some of these embodiments, theserves 106 may be geographically dispersed. In some cases, a farm 38 maybe administered as a single entity. In other embodiments, the serverfarm 38 comprises a plurality of server farms 38. In one embodiment, theserver farm executes one or more applications on behalf of one or moreclients 102.

The servers 106 within each farm 38 can be heterogeneous. One or more ofthe servers 106 can operate according to one type of operating systemplatform (e.g., WINDOWS NT, manufactured by Microsoft Corp. of Redmond,Wash.), while one or more of the other servers 106 can operate onaccording to another type of operating system platform (e.g., Unix orLinux). The servers 106 of each farm 38 do not need to be physicallyproximate to another server 106 in the same farm 38. Thus, the group ofservers 106 logically grouped as a farm 38 may be interconnected using awide-area network (WAN) connection or medium-area network (MAN)connection. For example, a farm 38 may include servers 106 physicallylocated in different continents or different regions of a continent,country, state, city, campus, or room. Data transmission speeds betweenservers 106 in the farm 38 can be increased if the servers 106 areconnected using a local-area network (LAN) connection or some form ofdirect connection.

Servers 106 may be referred to as a file server, application server, webserver, proxy server, or gateway server. In some embodiments, a server106 may have the capacity to function as either an application server oras a master application server. In one embodiment, a server 106 mayinclude an Active Directory. The clients 102 may also be referred to asclient nodes or endpoints. In some embodiments, a client 102 has thecapacity to function as both a client node seeking access toapplications on a server and as an application server providing accessto hosted applications for other clients 102 a-102 n.

In some embodiments, a client 102 communicates with a server 106. In oneembodiment, the client 102 communicates directly with one of the servers106 in a farm 38. In another embodiment, the client 102 executes aprogram neighborhood application to communicate with a server 106 in afarm 38. In still another embodiment, the server 106 provides thefunctionality of a master node. In some embodiments, the client 102communicates with the server 106 in the farm 38 through a network 104.Over the network 104, the client 102 can, for example, request executionof various applications hosted by the servers 106 a-106 n in the farm 38and receive output of the results of the application execution fordisplay. In some embodiments, only the master node provides thefunctionality required to identify and provide address informationassociated with a server 106′ hosting a requested application.

In one embodiment, the server 106 provides functionality of a webserver. In another embodiment, the server 106 a receives requests fromthe client 102, forwards the requests to a second server 106 b andresponds to the request by the client 102 with a response to the requestfrom the server 106 b. In still another embodiment, the server 106acquires an enumeration of applications available to the client 102 andaddress information associated with a server 106 hosting an applicationidentified by the enumeration of applications. In yet anotherembodiment, the server 106 presents the response to the request to theclient 102 using a web interface. In one embodiment, the client 102communicates directly with the server 106 to access the identifiedapplication. In another embodiment, the client 102 receives applicationoutput data, such as display data, generated by an execution of theidentified application on the server 106.

Referring now to FIG. 1B, an embodiment of a network environmentdeploying multiple appliances 200 is depicted. A first appliance 200 maybe deployed on a first network 104 and a second appliance 200′ on asecond network 104′. For example a corporate enterprise may deploy afirst appliance 200 at a branch office and a second appliance 200′ at adata center. In another embodiment, the first appliance 200 and secondappliance 200′ are deployed on the same network 104 or network 104. Forexample, a first appliance 200 may be deployed for a first server farm38, and a second appliance 200 may be deployed for a second server farm38′. In another example, a first appliance 200 may be deployed at afirst branch office while the second appliance 200′ is deployed at asecond branch office′. In some embodiments, the first appliance 200 andsecond appliance 200′ work in cooperation or in conjunction with eachother to accelerate network traffic or the delivery of application anddata between a client and a server

Referring now to FIG. 1C, another embodiment of a network environmentdeploying the appliance 200 with one or more other types of appliances,such as between one or more WAN optimization appliance 205, 205′ isdepicted. For example a first WAN optimization appliance 205 is shownbetween networks 104 and 104′ and a second WAN optimization appliance205′ may be deployed between the appliance 200 and one or more servers106. By way of example, a corporate enterprise may deploy a first WANoptimization appliance 205 at a branch office and a second WANoptimization appliance 205′ at a data center. In some embodiments, theappliance 205 may be located on network 104′. In other embodiments, theappliance 205′ may be located on network 104. In some embodiments, theappliance 205′ may be located on network 104′ or network 104″. In oneembodiment, the appliance 205 and 205′ are on the same network. Inanother embodiment, the appliance 205 and 205′ are on differentnetworks. In another example, a first WAN optimization appliance 205 maybe deployed for a first server farm 38 and a second WAN optimizationappliance 205′ for a second server farm 38′

In one embodiment, the appliance 205 is a device for accelerating,optimizing or otherwise improving the performance, operation, or qualityof service of any type and form of network traffic, such as traffic toand/or from a WAN connection. In some embodiments, the appliance 205 isa performance enhancing proxy. In other embodiments, the appliance 205is any type and form of WAN optimization or acceleration device,sometimes also referred to as a WAN optimization controller. In oneembodiment, the appliance 205 is any of the product embodiments referredto as WANScaler manufactured by Citrix Systems, Inc. of Ft. Lauderdale,Fla. In other embodiments, the appliance 205 includes any of the productembodiments referred to as BIG-IP link controller and WANjetmanufactured by F5 Networks, Inc. of Seattle, Wash. In anotherembodiment, the appliance 205 includes any of the WX and WXC WANacceleration device platforms manufactured by Juniper Networks, Inc. ofSunnyvale, Calif. In some embodiments, the appliance 205 includes any ofthe steelhead line of WAN optimization appliances manufactured byRiverbed Technology of San Francisco, Calif. In other embodiments, theappliance 205 includes any of the WAN related devices manufactured byExpand Networks Inc. of Roseland, N.J. In one embodiment, the appliance205 includes any of the WAN related appliances manufactured by PacketeerInc. of Cupertino, California, such as the PacketShaper, iShared, andSkyX product embodiments provided by Packeteer. In yet anotherembodiment, the appliance 205 includes any WAN related appliances and/orsoftware manufactured by Cisco Systems, Inc. of San Jose, Calif., suchas the Cisco Wide Area Network Application Services software and networkmodules, and Wide Area Network engine appliances.

In one embodiment, the appliance 205 provides application and dataacceleration services for branch-office or remote offices. In oneembodiment, the appliance 205 includes optimization of Wide Area FileServices (WAFS). In another embodiment, the appliance 205 acceleratesthe delivery of files, such as via the Common Internet File System(CIFS) protocol. In other embodiments, the appliance 205 providescaching in memory and/or storage to accelerate delivery of applicationsand data. In one embodiment, the appliance 205 provides compression ofnetwork traffic at any level of the network stack or at any protocol ornetwork layer. In another embodiment, the appliance 205 providestransport layer protocol optimizations, flow control, performanceenhancements or modifications and/or management to accelerate deliveryof applications and data over a WAN connection. For example, in oneembodiment, the appliance 205 provides Transport Control Protocol (TCP)optimizations. In other embodiments, the appliance 205 providesoptimizations, flow control, performance enhancements or modificationsand/or management for any session or application layer protocol.

In another embodiment, the appliance 205 encoded any type and form ofdata or information into custom or standard TCP and/or IP header fieldsor option fields of network packet to announce presence, functionalityor capability to another appliance 205′. In another embodiment, anappliance 205′ may communicate with another appliance 205′ using dataencoded in both TCP and/or IP header fields or options. For example, theappliance may use TCP option(s) or IP header fields or options tocommunicate one or more parameters to be used by the appliances 205,205′ in performing functionality, such as WAN acceleration, or forworking in conjunction with each other.

In some embodiments, the appliance 200 preserves any of the informationencoded in TCP and/or IP header and/or option fields communicatedbetween appliances 205 and 205′. For example, the appliance 200 mayterminate a transport layer connection traversing the appliance 200,such as a transport layer connection from between a client and a servertraversing appliances 205 and 205′. In one embodiment, the appliance 200identifies and preserves any encoded information in a transport layerpacket transmitted by a first appliance 205 via a first transport layerconnection and communicates a transport layer packet with the encodedinformation to a second appliance 205′ via a second transport layerconnection.

Referring now to FIG. 1D, a network environment for delivering and/oroperating a computing environment on a client 102 is depicted. In someembodiments, a server 106 includes an application delivery system 190for delivering a computing environment or an application and/or datafile to one or more clients 102. In brief overview, a client 10 is incommunication with a server 106 via network 104, 104′ and appliance 200.For example, the client 102 may reside in a remote office of a company,e.g., a branch office, and the server 106 may reside at a corporate datacenter. The client 102 comprises a client agent 120, and a computingenvironment 15. The computing environment 15 may execute or operate anapplication that accesses, processes or uses a data file. The computingenvironment 15, application and/or data file may be delivered via theappliance 200 and/or the server 106.

In some embodiments, the appliance 200 accelerates delivery of acomputing environment 15, or any portion thereof, to a client 102. Inone embodiment, the appliance 200 accelerates the delivery of thecomputing environment 15 by the application delivery system 190. Forexample, the embodiments described herein may be used to acceleratedelivery of a streaming application and data file processable by theapplication from a central corporate data center to a remote userlocation, such as a branch office of the company. In another embodiment,the appliance 200 accelerates transport layer traffic between a client102 and a server 106. The appliance 200 may provide accelerationtechniques for accelerating any transport layer payload from a server106 to a client 102, such as: 1) transport layer connection pooling, 2)transport layer connection multiplexing, 3) transport control protocolbuffering, 4) compression and 5) caching. In some embodiments, theappliance 200 provides load balancing of servers 106 in responding torequests from clients 102. In other embodiments, the appliance 200 actsas a proxy or access server to provide access to the one or more servers106. In another embodiment, the appliance 200 provides a secure virtualprivate network connection from a first network 104 of the client 102 tothe second network 104′ of the server 106, such as an SSL VPNconnection. It yet other embodiments, the appliance 200 providesapplication firewall security, control and management of the connectionand communications between a client 102 and a server 106.

In some embodiments, the application delivery management system 190provides application delivery techniques to deliver a computingenvironment to a desktop of a user, remote or otherwise, based on aplurality of execution methods and based on any authentication andauthorization policies applied via a policy engine 195. With thesetechniques, a remote user may obtain a computing environment and accessto server stored applications and data files from any network connecteddevice 100. In one embodiment, the application delivery system 190 mayreside or execute on a server 106. In another embodiment, theapplication delivery system 190 may reside or execute on a plurality ofservers 106 a-106 n. In some embodiments, the application deliverysystem 190 may execute in a server farm 38. In one embodiment, theserver 106 executing the application delivery system 190 may also storeor provide the application and data file. In another embodiment, a firstset of one or more servers 106 may execute the application deliverysystem 190, and a different server 106 n may store or provide theapplication and data file. In some embodiments, each of the applicationdelivery system 190, the application, and data file may reside or belocated on different servers. In yet another embodiment, any portion ofthe application delivery system 190 may reside, execute or be stored onor distributed to the appliance 200, or a plurality of appliances.

The client 102 may include a computing environment 15 for executing anapplication that uses or processes a data file. The client 102 vianetworks 104, 104′ and appliance 200 may request an application and datafile from the server 106. In one embodiment, the appliance 200 mayforward a request from the client 102 to the server 106. For example,the client 102 may not have the application and data file stored oraccessible locally. In response to the request, the application deliverysystem 190 and/or server 106 may deliver the application and data fileto the client 102. For example, in one embodiment, the server 106 maytransmit the application as an application stream to operate incomputing environment 15 on client 102.

In some embodiments, the application delivery system 190 comprises anyportion of the Citrix Access Suite™ by Citrix Systems, Inc., such as theMetaFrame or Citrix Presentation Server™ and/or any of the Microsoft®Windows Terminal Services manufactured by the Microsoft Corporation. Inone embodiment, the application delivery system 190 may deliver one ormore applications to clients 102 or users via a remote-display protocolor otherwise via remote-based or server-based computing. In anotherembodiment, the application delivery system 190 may deliver one or moreapplications to clients or users via steaming of the application.

In one embodiment, the application delivery system 190 includes a policyengine 195 for controlling and managing the access to, selection ofapplication execution methods and the delivery of applications. In someembodiments, the policy engine 195 determines the one or moreapplications a user or client 102 may access. In another embodiment, thepolicy engine 195 determines how the application should be delivered tothe user or client 102, e.g., the method of execution. In someembodiments, the application delivery system 190 provides a plurality ofdelivery techniques from which to select a method of applicationexecution, such as a server-based computing, streaming or delivering theapplication locally to the client 120 for local execution.

In one embodiment, a client 102 requests execution of an applicationprogram and the application delivery system 190 comprising a server 106selects a method of executing the application program. In someembodiments, the server 106 receives credentials from the client 102. Inanother embodiment, the server 106 receives a request for an enumerationof available applications from the client 102. In one embodiment, inresponse to the request or receipt of credentials, the applicationdelivery system 190 enumerates a plurality of application programsavailable to the client 102. The application delivery system 190receives a request to execute an enumerated application. The applicationdelivery system 190 selects one of a predetermined number of methods forexecuting the enumerated application, for example, responsive to apolicy of a policy engine. The application delivery system 190 mayselect a method of execution of the application enabling the client 102to receive application-output data generated by execution of theapplication program on a server 106. The application delivery system 190may select a method of execution of the application enabling the localmachine 10 to execute the application program locally after retrieving aplurality of application files comprising the application. In yetanother embodiment, the application delivery system 190 may select amethod of execution of the application to stream the application via thenetwork 104 to the client 102.

A client 102 may execute, operate or otherwise provide an application,which can be any type and/or form of software, program, or executableinstructions such as any type and/or form of web browser, web-basedclient, client-server application, a thin-client computing client, anActiveX control, or a Java applet, or any other type and/or form ofexecutable instructions capable of executing on client 102. In someembodiments, the application may be a server-based or a remote-basedapplication executed on behalf of the client 102 on a server 106. In oneembodiments the server 106 may display output to the client 102 usingany thin-client or remote-display protocol, such as the IndependentComputing Architecture (ICA) protocol manufactured by Citrix Systems,Inc. of Ft. Lauderdale, Fla. or the Remote Desktop Protocol (RDP)manufactured by the Microsoft Corporation of Redmond, Wash. Theapplication can use any type of protocol and it can be, for example, anHTTP client, an FTP client, an Oscar client, or a Telnet client. Inother embodiments, the application comprises any type of softwarerelated to VoIP communications, such as a soft IP telephone. In furtherembodiments, the application comprises any application related toreal-time data communications, such as applications for streaming videoand/or audio.

In some embodiments, the server 106 or a server farm 38 may be runningone or more applications, such as an application providing a thin-clientcomputing or remote display presentation application. In one embodiment,the server 106 or server farm 38 executes as an application, any portionof the Citrix Access Suite™ by Citrix Systems, Inc., such as theMetaFrame or Citrix Presentation Server™, and/or any of the Microsoft®Windows Terminal Services manufactured by the Microsoft Corporation. Inone embodiment, the application is an ICA client, developed by CitrixSystems, Inc. of Fort Lauderdale, Fla. In other embodiments, theapplication includes a Remote Desktop (RDP) client, developed byMicrosoft Corporation of Redmond, Wash. Also, the server 106 may run anapplication, which for example, may be an application server providingemail services such as Microsoft Exchange manufactured by the MicrosoftCorporation of Redmond, Wash., a web or Internet server, or a desktopsharing server, or a collaboration server. In some embodiments, any ofthe applications may comprise any type of hosted service or products,such as GoToMeeting™ provided by Citrix Online Division, Inc. of SantaBarbara, California, WebEx™ provided by WebEx, Inc. of Santa Clara,Calif., or Microsoft Office Live Meeting provided by MicrosoftCorporation of Redmond, Wash.

Still referring to FIG. 1D, an embodiment of the network environment mayinclude a monitoring server 106A. The monitoring server 106A may includeany type and form performance monitoring service 198. The performancemonitoring service 198 may include monitoring, measurement and/ormanagement software and/or hardware, including data collection,aggregation, analysis, management and reporting. In one embodiment, theperformance monitoring service 198 includes one or more monitoringagents 197. The monitoring agent 197 includes any software, hardware orcombination thereof for performing monitoring, measurement and datacollection activities on a device, such as a client 102, server 106 oran appliance 200, 205. In some embodiments, the monitoring agent 197includes any type and form of script, such as Visual Basic script, orJavascript. In one embodiment, the monitoring agent 197 executestransparently to any application and/or user of the device. In someembodiments, the monitoring agent 197 is installed and operatedunobtrusively to the application or client. In yet another embodiment,the monitoring agent 197 is installed and operated without anyinstrumentation for the application or device.

In some embodiments, the monitoring agent 197 monitors, measures andcollects data on a predetermined frequency. In other embodiments, themonitoring agent 197 monitors, measures and collects data based upondetection of any type and form of event. For example, the monitoringagent 197 may collect data upon detection of a request for a web page orreceipt of an HTTP response. In another example, the monitoring agent197 may collect data upon detection of any user input events, such as amouse click. The monitoring agent 197 may report or provide anymonitored, measured or collected data to the monitoring service 198. Inone embodiment, the monitoring agent 197 transmits information to themonitoring service 198 according to a schedule or a predeterminedfrequency. In another embodiment, the monitoring agent 197 transmitsinformation to the monitoring service 198 upon detection of an event.

In some embodiments, the monitoring service 198 and/or monitoring agent197 performs monitoring and performance measurement of any networkresource or network infrastructure element, such as a client, server,server farm, appliance 200, appliance 205, or network connection. In oneembodiment, the monitoring service 198 and/or monitoring agent 197performs monitoring and performance measurement of any transport layerconnection, such as a TCP or UDP connection. In another embodiment, themonitoring service 198 and/or monitoring agent 197 monitors and measuresnetwork latency. In yet one embodiment, the monitoring service 198and/or monitoring agent 197 monitors and measures bandwidth utilization.

In other embodiments, the monitoring service 198 and/or monitoring agent197 monitors and measures end-user response times. In some embodiments,the monitoring service 198 performs monitoring and performancemeasurement of an application. In another embodiment, the monitoringservice 198 and/or monitoring agent 197 performs monitoring andperformance measurement of any session or connection to the application.In one embodiment, the monitoring service 198 and/or monitoring agent197 monitors and measures performance of a browser. In anotherembodiment, the monitoring service 198 and/or monitoring agent 197monitors and measures performance of HTTP based transactions. In someembodiments, the monitoring service 198 and/or monitoring agent 197monitors and measures performance of a Voice over IP (VoIP) applicationor session. In other embodiments, the monitoring service 198 and/ormonitoring agent 197 monitors and measures performance of a remotedisplay protocol application, such as an ICA client or RDP client. Inyet another embodiment, the monitoring service 198 and/or monitoringagent 197 monitors and measures performance of any type and form ofstreaming media. In still a further embodiment, the monitoring service198 and/or monitoring agent 197 monitors and measures performance of ahosted application or a Software-As-A-Service (SaaS) delivery model.

In some embodiments, the monitoring service 198 and/or monitoring agent197 performs monitoring and performance measurement of one or moretransactions, requests or responses related to application. In otherembodiments, the monitoring service 198 and/or monitoring agent 197monitors and measures any portion of an application layer stack, such asany .NET or J2EE calls. In one embodiment, the monitoring service 198and/or monitoring agent 197 monitors and measures database or SQLtransactions. In yet another embodiment, the monitoring service 198and/or monitoring agent 197 monitors and measures any method, functionor application programming interface (API) call.

In one embodiment, the monitoring service 198 and/or monitoring agent197 performs monitoring and performance measurement of a delivery ofapplication and/or data from a server to a client via one or moreappliances, such as appliance 200 and/or appliance 205. In someembodiments, the monitoring service 198 and/or monitoring agent 197monitors and measures performance of delivery of a virtualizedapplication. In other embodiments, the monitoring service 198 and/ormonitoring agent 197 monitors and measures performance of delivery of astreaming application. In another embodiment, the monitoring service 198and/or monitoring agent 197 monitors and measures performance ofdelivery of a desktop application to a client and/or the execution ofthe desktop application on the client. In another embodiment, themonitoring service 198 and/or monitoring agent 197 monitors and measuresperformance of a client/server application.

In one embodiment, the monitoring service 198 and/or monitoring agent197 is designed and constructed to provide application performancemanagement for the application delivery system 190. For example, themonitoring service 198 and/or monitoring agent 197 may monitor, measureand manage the performance of the delivery of applications via theCitrix Presentation Server. In this example, the monitoring service 198and/or monitoring agent 197 monitors individual ICA sessions. Themonitoring service 198 and/or monitoring agent 197 may measure the totaland per session system resource usage, as well as application andnetworking performance. The monitoring service 198 and/or monitoringagent 197 may identify the active servers for a given user and/or usersession. In some embodiments, the monitoring service 198 and/ormonitoring agent 197 monitors back-end connections between theapplication delivery system 190 and an application and/or databaseserver. The monitoring service 198 and/or monitoring agent 197 maymeasure network latency, delay and volume per user-session or ICAsession.

In some embodiments, the monitoring service 198 and/or monitoring agent197 measures and monitors memory usage for the application deliverysystem 190, such as total memory usage, per user session and/or perprocess. In other embodiments, the monitoring service 198 and/ormonitoring agent 197 measures and monitors CPU usage the applicationdelivery system 190, such as total CPU usage, per user session and/orper process. In another embodiments, the monitoring service 198 and/ormonitoring agent 197 measures and monitors the time required to log-into an application, a server, or the application delivery system, such asCitrix Presentation Server. In one embodiment, the monitoring service198 and/or monitoring agent 197 measures and monitors the duration auser is logged into an application, a server, or the applicationdelivery system 190. In some embodiments, the monitoring service 198and/or monitoring agent 197 measures and monitors active and inactivesession counts for an application, server or application delivery systemsession. In yet another embodiment, the monitoring service 198 and/ormonitoring agent 197 measures and monitors user session latency.

In yet further embodiments, the monitoring service 198 and/or monitoringagent 197 measures and monitors measures and monitors any type and formof server metrics. In one embodiment, the monitoring service 198 and/ormonitoring agent 197 measures and monitors metrics related to systemmemory, CPU usage, and disk storage. In another embodiment, themonitoring service 198 and/or monitoring agent 197 measures and monitorsmetrics related to page faults, such as page faults per second. In otherembodiments, the monitoring service 198 and/or monitoring agent 197measures and monitors round-trip time metrics. In yet anotherembodiment, the monitoring service 198 and/or monitoring agent 197measures and monitors metrics related to application crashes, errorsand/or hangs.

In some embodiments, the monitoring service 198 and monitoring agent 198includes any of the product embodiments referred to as EdgeSightmanufactured by Citrix Systems, Inc. of Ft. Lauderdale, Fla. In anotherembodiment, the performance monitoring service 198 and/or monitoringagent 198 includes any portion of the product embodiments referred to asthe TrueView product suite manufactured by the Symphoniq Corporation ofPalo Alto, Calif. In one embodiment, the performance monitoring service198 and/or monitoring agent 198 includes any portion of the productembodiments referred to as the TeaLeaf CX product suite manufactured bythe TeaLeaf Technology Inc. of San Francisco, Calif. In otherembodiments, the performance monitoring service 198 and/or monitoringagent 198 includes any portion of the business service managementproducts, such as the BMC Performance Manager and Patrol products,manufactured by BMC Software, Inc. of Houston, Texas.

The client 102, server 106, and appliance 200 may be deployed as and/orexecuted on any type and form of computing device, such as a computer,network device or appliance capable of communicating on any type andform of network and performing the operations described herein. FIGS. 1Eand 1F depict block diagrams of a computing device 100 useful forpracticing an embodiment of the client 102, server 106 or appliance 200.As shown in FIGS. 1E and 1F, each computing device 100 includes acentral processing unit 101, and a main memory unit 122. As shown inFIG. 1E, a computing device 100 may include a visual display device 124,a keyboard 126 and/or a pointing device 127, such as a mouse. Eachcomputing device 100 may also include additional optional elements, suchas one or more input/output devices 130 a-130 b (generally referred tousing reference numeral 130), and a cache memory 140 in communicationwith the central processing unit 101.

The central processing unit 101 is any logic circuitry that responds toand processes instructions fetched from the main memory unit 122. Inmany embodiments, the central processing unit is provided by amicroprocessor unit, such as: those manufactured by Intel Corporation ofMountain View, Calif.; those manufactured by Motorola Corporation ofSchaumburg, Illinois; those manufactured by Transmeta Corporation ofSanta Clara, Calif.; the RS/6000 processor, those manufactured byInternational Business Machines of White Plains, New York; or thosemanufactured by Advanced Micro Devices of Sunnyvale, Calif. Thecomputing device 100 may be based on any of these processors, or anyother processor capable of operating as described herein.

Main memory unit 122 may be one or more memory chips capable of storingdata and allowing any storage location to be directly accessed by themicroprocessor 101, such as Static random access memory (SRAM), BurstSRAM or SynchBurst SRAM (BSRAM), Dynamic random access memory (DRAM),Fast Page Mode DRAM (FPM DRAM), Enhanced DRAM (EDRAM), Extended DataOutput RAM (EDO RAM), Extended Data Output DRAM (EDO DRAM), BurstExtended Data Output DRAM (BEDO DRAM), Enhanced DRAM (EDRAM),synchronous DRAM (SDRAM), JEDEC SRAM, PC100 SDRAM, Double Data RateSDRAM (DDR SDRAM), Enhanced SDRAM (ESDRAM), SyncLink DRAM (SLDRAM),Direct Rambus DRAM (DRDRAM), or Ferroelectric RAM (FRAM). The mainmemory 122 may be based on any of the above described memory chips, orany other available memory chips capable of operating as describedherein. In the embodiment shown in FIG. 1E, the processor 101communicates with main memory 122 via a system bus 150 (described inmore detail below). FIG. 1F depicts an embodiment of a computing device100 in which the processor communicates directly with main memory 122via a memory port 103. For example, in FIG. 1F the main memory 122 maybe DRDRAM.

FIG. 1F depicts an embodiment in which the main processor 101communicates directly with cache memory 140 via a secondary bus,sometimes referred to as a backside bus. In other embodiments, the mainprocessor 101 communicates with cache memory 140 using the system bus150. Cache memory 140 typically has a faster response time than mainmemory 122 and is typically provided by SRAM, BSRAM, or EDRAM. In theembodiment shown in FIG. 1F, the processor 101 communicates with variousI/O devices 130 via a local system bus 150. Various busses may be usedto connect the central processing unit 101 to any of the I/O devices130, including a VESA VL bus, an ISA bus, an EISA bus, a MicroChannelArchitecture (MCA) bus, a PCI bus, a PCI-X bus, a PCI-Express bus, or aNuBus. For embodiments in which the I/O device is a video display 124,the processor 101 may use an Advanced Graphics Port (AGP) to communicatewith the display 124. FIG. 1F depicts an embodiment of a computer 100 inwhich the main processor 101 communicates directly with I/O device 130 bvia HyperTransport, Rapid I/O, or InfiniBand. FIG. 1F also depicts anembodiment in which local busses and direct communication are mixed: theprocessor 101 communicates with I/O device 130 b using a localinterconnect bus while communicating with I/O device 130 a directly.

The computing device 100 may support any suitable installation device116, such as a floppy disk drive for receiving floppy disks such as3.5-inch, 5.25-inch disks or ZIP disks, a CD-ROM drive, a CD-R/RW drive,a DVD-ROM drive, tape drives of various formats, USB device, hard-driveor any other device suitable for installing software and programs suchas any client agent 120, or portion thereof. The computing device 100may further comprise a storage device 128, such as one or more hard diskdrives or redundant arrays of independent disks, for storing anoperating system and other related software, and for storing applicationsoftware programs such as any program related to the client agent 120.Optionally, any of the installation devices 116 could also be used asthe storage device 128. Additionally, the operating system and thesoftware can be run from a bootable medium, for example, a bootable CD,such as KNOPPIX®, a bootable CD for GNU/Linux that is available as aGNU/Linux distribution from knoppix.net.

Furthermore, the computing device 100 may include a network interface118 to interface to a Local Area Network (LAN), Wide Area Network (WAN)or the Internet through a variety of connections including, but notlimited to, standard telephone lines, LAN or WAN links (e.g., 802.11,T1, T3, 56 kb, X.25), broadband connections (e.g., ISDN, Frame Relay,ATM), wireless connections, or some combination of any or all of theabove. The network interface 118 may comprise a built-in networkadapter, network interface card, PCMCIA network card, card bus networkadapter, wireless network adapter, USB network adapter, modem or anyother device suitable for interfacing the computing device 100 to anytype of network capable of communication and performing the operationsdescribed herein. A wide variety of I/O devices 130 a-130 n may bepresent in the computing device 100. Input devices include keyboards,mice, trackpads, trackballs, microphones, and drawing tablets. Outputdevices include video displays, speakers, inkjet printers, laserprinters, and dye-sublimation printers. The I/O devices 130 may becontrolled by an I/O controller 123 as shown in FIG. 1E. The I/Ocontroller may control one or more I/O devices such as a keyboard 126and a pointing device 127, e.g., a mouse or optical pen. Furthermore, anI/O device may also provide storage 128 and/or an installation medium116 for the computing device 100. In still other embodiments, thecomputing device 100 may provide USB connections to receive handheld USBstorage devices such as the USB Flash Drive line of devices manufacturedby Twintech Industry, Inc. of Los Alamitos, California.

In some embodiments, the computing device 100 may comprise or beconnected to multiple display devices 124 a-124 n, which each may be ofthe same or different type and/or form. As such, any of the I/O devices130 a-130 n and/or the I/O controller 123 may comprise any type and/orform of suitable hardware, software, or combination of hardware andsoftware to support, enable or provide for the connection and use ofmultiple display devices 124 a-124 n by the computing device 100. Forexample, the computing device 100 may include any type and/or form ofvideo adapter, video card, driver, and/or library to interface,communicate, connect or otherwise use the display devices 124 a-124 n.In one embodiment, a video adapter may comprise multiple connectors tointerface to multiple display devices 124 a-124 n. In other embodiments,the computing device 100 may include multiple video adapters, with eachvideo adapter connected to one or more of the display devices 124 a-124n. In some embodiments, any portion of the operating system of thecomputing device 100 may be configured for using multiple displays 124a-124 n. In other embodiments, one or more of the display devices 124a-124 n may be provided by one or more other computing devices, such ascomputing devices 100 a and 100 b connected to the computing device 100,for example, via a network. These embodiments may include any type ofsoftware designed and constructed to use another computer's displaydevice as a second display device 124 a for the computing device 100.One ordinarily skilled in the art will recognize and appreciate thevarious ways and embodiments that a computing device 100 may beconfigured to have multiple display devices 124 a-124 n.

In further embodiments, an I/O device 130 may be a bridge 170 betweenthe system bus 150 and an external communication bus, such as a USB bus,an Apple Desktop Bus, an RS-232 serial connection, a SCSI bus, aFireWire bus, a FireWire 800 bus, an Ethernet bus, an AppleTalk bus, aGigabit Ethernet bus, an Asynchronous Transfer Mode bus, a HIPPI bus, aSuper HIPPI bus, a SerialPlus bus, a SCl/LAMP bus, a FibreChannel bus,or a Serial Attached small computer system interface bus.

A computing device 100 of the sort depicted in FIGS. 1E and 1F typicallyoperate under the control of operating systems, which control schedulingof tasks and access to system resources. The computing device 100 can berunning any operating system such as any of the versions of theMicrosoft® Windows operating systems, the different releases of the Unixand Linux operating systems, any version of the Mac OS® for Macintoshcomputers, any embedded operating system, any real-time operatingsystem, any open source operating system, any proprietary operatingsystem, any operating systems for mobile computing devices, or any otheroperating system capable of running on the computing device andperforming the operations described herein. Typical operating systemsinclude: WINDOWS 3.x, WINDOWS 95, WINDOWS 98, WINDOWS 2000, WINDOWS NT3.51, WINDOWS NT 4.0, WINDOWS CE, and WINDOWS XP, all of which aremanufactured by Microsoft Corporation of Redmond, Wash.; MacOS,manufactured by Apple Computer of Cupertino, California; OS/2,manufactured by International Business Machines of Armonk, N.Y.; andLinux, a freely-available operating system distributed by Caldera Corp.of Salt Lake City, Utah, or any type and/or form of a Unix operatingsystem, among others.

In other embodiments, the computing device 100 may have differentprocessors, operating systems, and input devices consistent with thedevice. For example, in one embodiment the computer 100 is a Treo 180,270, 1060, 600 or 650 smart phone manufactured by Palm, Inc. In thisembodiment, the Treo smart phone is operated under the control of thePalmOS operating system and includes a stylus input device as well as afive-way navigator device. Moreover, the computing device 100 can be anyworkstation, desktop computer, laptop or notebook computer, server,handheld computer, mobile telephone, any other computer, or other formof computing or telecommunications device that is capable ofcommunication and that has sufficient processor power and memorycapacity to perform the operations described herein.

As shown in FIG. 1G, the computing device 100 may comprise multipleprocessors and may provide functionality for simultaneous execution ofinstructions or for simultaneous execution of one instruction on morethan one piece of data. In some embodiments, the computing device 100may comprise a parallel processor with one or more cores. In one ofthese embodiments, the computing device 100 is a shared memory paralleldevice, with multiple processors and/or multiple processor cores,accessing all available memory as a single global address space. Inanother of these embodiments, the computing device 100 is a distributedmemory parallel device with multiple processors each accessing localmemory only. In still another of these embodiments, the computing device100 has both some memory which is shared and some memory which can onlybe accessed by particular processors or subsets of processors. In stilleven another of these embodiments, the computing device 100, such as amulti-core microprocessor, combines two or more independent processorsinto a single package, often a single integrated circuit (IC). In yetanother of these embodiments, the computing device 100 includes a chiphaving a CELL BROADBAND ENGINE architecture and including a Powerprocessor element and a plurality of synergistic processing elements,the Power processor element and the plurality of synergistic processingelements linked together by an internal high speed bus, which may bereferred to as an element interconnect bus.

In some embodiments, the processors provide functionality for executionof a single instruction simultaneously on multiple pieces of data(SIMD). In other embodiments, the processors provide functionality forexecution of multiple instructions simultaneously on multiple pieces ofdata (MIMD). In still other embodiments, the processor may use anycombination of SIMD and MIMD cores in a single device.

In some embodiments, the computing device 100 may comprise a graphicsprocessing unit. In one of these embodiments, depicted in FIG. 1H, thecomputing device 100 includes at least one central processing unit 101and at least one graphics processing unit. In another of theseembodiments, the computing device 100 includes at least one parallelprocessing unit and at least one graphics processing unit. In stillanother of these embodiments, the computing device 100 includes aplurality of processing units of any type, one of the plurality ofprocessing units comprising a graphics processing unit.

In some embodiments, a first computing device 100 a executes anapplication on behalf of a user of a client computing device 100 b. Inother embodiments, a computing device 100 a executes a virtual machine,which provides an execution session within which applications execute onbehalf of a user or a client computing devices 100 b. In one of theseembodiments, the execution session is a hosted desktop session. Inanother of these embodiments, the computing device 100 executes aterminal services session. The terminal services session may provide ahosted desktop environment. In still another of these embodiments, theexecution session provides access to a computing environment, which maycomprise one or more of: an application, a plurality of applications, adesktop application, and a desktop session in which one or moreapplications may execute.

B. Appliance Architecture

FIG. 2A illustrates an example embodiment of the appliance 200. Thearchitecture of the appliance 200 in FIG. 2A is provided by way ofillustration only and is not intended to be limiting. As shown in FIG.2, appliance 200 comprises a hardware layer 206 and a software layerdivided into a user space 202 and a kernel space 204.

Hardware layer 206 provides the hardware elements upon which programsand services within kernel space 204 and user space 202 are executed.Hardware layer 206 also provides the structures and elements which allowprograms and services within kernel space 204 and user space 202 tocommunicate data both internally and externally with respect toappliance 200. As shown in FIG. 2, the hardware layer 206 includes aprocessing unit 262 for executing software programs and services, amemory 264 for storing software and data, network ports 266 fortransmitting and receiving data over a network, and an encryptionprocessor 260 for performing functions related to Secure Sockets Layerprocessing of data transmitted and received over the network. In someembodiments, the central processing unit 262 may perform the functionsof the encryption processor 260 in a single processor. Additionally, thehardware layer 206 may comprise multiple processors for each of theprocessing unit 262 and the encryption processor 260. The processor 262may include any of the processors 101 described above in connection withFIGS. 1E and 1F. For example, in one embodiment, the appliance 200comprises a first processor 262 and a second processor 262′. In otherembodiments, the processor 262 or 262′ comprises a multi-core processor.

Although the hardware layer 206 of appliance 200 is generallyillustrated with an encryption processor 260, processor 260 may be aprocessor for performing functions related to any encryption protocol,such as the Secure Socket Layer (SSL) or Transport Layer Security (TLS)protocol. In some embodiments, the processor 260 may be a generalpurpose processor (GPP), and in further embodiments, may have executableinstructions for performing processing of any security related protocol.

Although the hardware layer 206 of appliance 200 is illustrated withcertain elements in FIG. 2, the hardware portions or components ofappliance 200 may comprise any type and form of elements, hardware orsoftware, of a computing device, such as the computing device 100illustrated and discussed herein in conjunction with FIGS. 1E and 1F. Insome embodiments, the appliance 200 may comprise a server, gateway,router, switch, bridge or other type of computing or network device, andhave any hardware and/or software elements associated therewith.

The operating system of appliance 200 allocates, manages, or otherwisesegregates the available system memory into kernel space 204 and userspace 204. In example software architecture 200, the operating systemmay be any type and/or form of Unix operating system although theinvention is not so limited. As such, the appliance 200 can be runningany operating system such as any of the versions of the Microsoft®Windows operating systems, the different releases of the Unix and Linuxoperating systems, any version of the Mac OS® for Macintosh computers,any embedded operating system, any network operating system, anyreal-time operating system, any open source operating system, anyproprietary operating system, any operating systems for mobile computingdevices or network devices, or any other operating system capable ofrunning on the appliance 200 and performing the operations describedherein.

The kernel space 204 is reserved for running the kernel 230, includingany device drivers, kernel extensions or other kernel related software.As known to those skilled in the art, the kernel 230 is the core of theoperating system, and provides access, control, and management ofresources and hardware-related elements of the application 104. Inaccordance with an embodiment of the appliance 200, the kernel space 204also includes a number of network services or processes working inconjunction with a cache manager 232, sometimes also referred to as theintegrated cache, the benefits of which are described in detail furtherherein. Additionally, the embodiment of the kernel 230 will depend onthe embodiment of the operating system installed, configured, orotherwise used by the device 200.

In one embodiment, the device 200 comprises one network stack 267, suchas a TCP/IP based stack, for communicating with the client 102 and/orthe server 106. In one embodiment, the network stack 267 is used tocommunicate with a first network, such as network 108, and a secondnetwork 110. In some embodiments, the device 200 terminates a firsttransport layer connection, such as a TCP connection of a client 102,and establishes a second transport layer connection to a server 106 foruse by the client 102, e.g., the second transport layer connection isterminated at the appliance 200 and the server 106. The first and secondtransport layer connections may be established via a single networkstack 267. In other embodiments, the device 200 may comprise multiplenetwork stacks, for example 267 and 267′, and the first transport layerconnection may be established or terminated at one network stack 267,and the second transport layer connection on the second network stack267′. For example, one network stack may be for receiving andtransmitting network packet on a first network, and another networkstack for receiving and transmitting network packets on a secondnetwork. In one embodiment, the network stack 267 comprises a buffer 243for queuing one or more network packets for transmission by theappliance 200.

As shown in FIG. 2, the kernel space 204 includes the cache manager 232,a high-speed layer 2-7 integrated packet engine 240, an encryptionengine 234, a policy engine 236 and multi-protocol compression logic238. Running these components or processes 232, 240, 234, 236 and 238 inkernel space 204 or kernel mode instead of the user space 202 improvesthe performance of each of these components, alone and in combination.Kernel operation means that these components or processes 232, 240, 234,236 and 238 run in the core address space of the operating system of thedevice 200. For example, running the encryption engine 234 in kernelmode improves encryption performance by moving encryption and decryptionoperations to the kernel, thereby reducing the number of transitionsbetween the memory space or a kernel thread in kernel mode and thememory space or a thread in user mode. For example, data obtained inkernel mode may not need to be passed or copied to a process or threadrunning in user mode, such as from a kernel level data structure to auser level data structure. In another aspect, the number of contextswitches between kernel mode and user mode are also reduced.Additionally, synchronization of and communications between any of thecomponents or processes 232, 240, 235, 236 and 238 can be performed moreefficiently in the kernel space 204.

In some embodiments, any portion of the components 232, 240, 234, 236and 238 may run or operate in the kernel space 204, while other portionsof these components 232, 240, 234, 236 and 238 may run or operate inuser space 202. In one embodiment, the appliance 200 uses a kernel-leveldata structure providing access to any portion of one or more networkpackets, for example, a network packet comprising a request from aclient 102 or a response from a server 106. In some embodiments, thekernel-level data structure may be obtained by the packet engine 240 viaa transport layer driver interface or filter to the network stack 267.The kernel-level data structure may comprise any interface and/or dataaccessible via the kernel space 204 related to the network stack 267,network traffic or packets received or transmitted by the network stack267. In other embodiments, the kernel-level data structure may be usedby any of the components or processes 232, 240, 234, 236 and 238 toperform the desired operation of the component or process. In oneembodiment, a component 232, 240, 234, 236 and 238 is running in kernelmode 204 when using the kernel-level data structure, while in anotherembodiment, the component 232, 240, 234, 236 and 238 is running in usermode when using the kernel-level data structure. In some embodiments,the kernel-level data structure may be copied or passed to a secondkernel-level data structure, or any desired user-level data structure.

The cache manager 232 may comprise software, hardware or any combinationof software and hardware to provide cache access, control and managementof any type and form of content, such as objects or dynamicallygenerated objects served by the originating servers 106. The data,objects or content processed and stored by the cache manager 232 maycomprise data in any format, such as a markup language, or communicatedvia any protocol. In some embodiments, the cache manager 232 duplicatesoriginal data stored elsewhere or data previously computed, generated ortransmitted, in which the original data may require longer access timeto fetch, compute or otherwise obtain relative to reading a cache memoryelement. Once the data is stored in the cache memory element, future usecan be made by accessing the cached copy rather than refetching orrecomputing the original data, thereby reducing the access time. In someembodiments, the cache memory element may comprise a data object inmemory 264 of device 200. In other embodiments, the cache memory elementmay comprise memory having a faster access time than memory 264. Inanother embodiment, the cache memory element may comprise any type andform of storage element of the device 200, such as a portion of a harddisk. In some embodiments, the processing unit 262 may provide cachememory for use by the cache manager 232. In yet further embodiments, thecache manager 232 may use any portion and combination of memory,storage, or the processing unit for caching data, objects, and othercontent.

Furthermore, the cache manager 232 includes any logic, functions, rules,or operations to perform any embodiments of the techniques of theappliance 200 described herein. For example, the cache manager 232includes logic or functionality to invalidate objects based on theexpiration of an invalidation time period or upon receipt of aninvalidation command from a client 102 or server 106. In someembodiments, the cache manager 232 may operate as a program, service,process or task executing in the kernel space 204, and in otherembodiments, in the user space 202. In one embodiment, a first portionof the cache manager 232 executes in the user space 202 while a secondportion executes in the kernel space 204. In some embodiments, the cachemanager 232 can comprise any type of general purpose processor (GPP), orany other type of integrated circuit, such as a Field Programmable GateArray (FPGA), Programmable Logic Device (PLD), or Application SpecificIntegrated Circuit (ASIC).

The policy engine 236 may include, for example, an intelligentstatistical engine or other programmable application(s). In oneembodiment, the policy engine 236 provides a configuration mechanism toallow a user to identify, specify, define or configure a caching policy.Policy engine 236, in some embodiments, also has access to memory tosupport data structures such as lookup tables or hash tables to enableuser-selected caching policy decisions. In other embodiments, the policyengine 236 may comprise any logic, rules, functions or operations todetermine and provide access, control and management of objects, data orcontent being cached by the appliance 200 in addition to access, controland management of security, network traffic, network access, compressionor any other function or operation performed by the appliance 200.Further examples of specific caching policies are further describedherein.

The encryption engine 234 comprises any logic, business rules, functionsor operations for handling the processing of any security relatedprotocol, such as SSL or TLS, or any function related thereto. Forexample, the encryption engine 234 encrypts and decrypts networkpackets, or any portion thereof, communicated via the appliance 200. Theencryption engine 234 may also setup or establish SSL or TLS connectionson behalf of the client 102 a-102 n, server 106 a-106 n, or appliance200. As such, the encryption engine 234 provides offloading andacceleration of SSL processing. In one embodiment, the encryption engine234 uses a tunneling protocol to provide a virtual private networkbetween a client 102 a-102 n and a server 106 a-106 n. In someembodiments, the encryption engine 234 is in communication with theEncryption processor 260. In other embodiments, the encryption engine234 comprises executable instructions running on the Encryptionprocessor 260.

The multi-protocol compression engine 238 comprises any logic, businessrules, function or operations for compressing one or more protocols of anetwork packet, such as any of the protocols used by the network stack267 of the device 200. In one embodiment, multi-protocol compressionengine 238 compresses bi-directionally between clients 102 a-102 n andservers 106 a-106 n any TCP/IP based protocol, including MessagingApplication Programming Interface (MAPI) (email), File Transfer Protocol(FTP), HyperText Transfer Protocol (HTTP), Common Internet File System(CIFS) protocol (file transfer), Independent Computing Architecture(ICA) protocol, Remote Desktop Protocol (RDP), Wireless ApplicationProtocol (WAP), Mobile IP protocol, and Voice Over IP (VoIP) protocol.In other embodiments, multi-protocol compression engine 238 providescompression of Hypertext Markup Language (HTML) based protocols and insome embodiments, provides compression of any markup languages, such asthe Extensible Markup Language (XML). In one embodiment, themulti-protocol compression engine 238 provides compression of anyhigh-performance protocol, such as any protocol designed for appliance200 to appliance 200 communications. In another embodiment, themulti-protocol compression engine 238 compresses any payload of or anycommunication using a modified transport control protocol, such asTransaction TCP (T/TCP), TCP with selection acknowledgements (TCP-SACK),TCP with large windows (TCP-LW), a congestion prediction protocol suchas the TCP-Vegas protocol, and a TCP spoofing protocol.

As such, the multi-protocol compression engine 238 acceleratesperformance for users accessing applications via desktop clients, e.g.,Microsoft Outlook and non-Web thin clients, such as any client launchedby popular enterprise applications like Oracle, SAP and Siebel, and evenmobile clients, such as the Pocket PC. In some embodiments, themulti-protocol compression engine 238 by executing in the kernel mode204 and integrating with packet processing engine 240 accessing thenetwork stack 267 is able to compress any of the protocols carried bythe TCP/IP protocol, such as any application layer protocol.

High speed layer 2-7 integrated packet engine 240, also generallyreferred to as a packet processing engine or packet engine, isresponsible for managing the kernel-level processing of packets receivedand transmitted by appliance 200 via network ports 266. The high speedlayer 2-7 integrated packet engine 240 may comprise a buffer for queuingone or more network packets during processing, such as for receipt of anetwork packet or transmission of a network packet. Additionally, thehigh speed layer 2-7 integrated packet engine 240 is in communicationwith one or more network stacks 267 to send and receive network packetsvia network ports 266. The high speed layer 2-7 integrated packet engine240 works in conjunction with encryption engine 234, cache manager 232,policy engine 236 and multi-protocol compression logic 238. Inparticular, encryption engine 234 is configured to perform SSLprocessing of packets, policy engine 236 is configured to performfunctions related to traffic management such as request-level contentswitching and request-level cache redirection, and multi-protocolcompression logic 238 is configured to perform functions related tocompression and decompression of data.

The high speed layer 2-7 integrated packet engine 240 includes a packetprocessing timer 242. In one embodiment, the packet processing timer 242provides one or more time intervals to trigger the processing ofincoming, i.e., received, or outgoing, i.e., transmitted, networkpackets. In some embodiments, the high speed layer 2-7 integrated packetengine 240 processes network packets responsive to the timer 242. Thepacket processing timer 242 provides any type and form of signal to thepacket engine 240 to notify, trigger, or communicate a time relatedevent, interval or occurrence. In many embodiments, the packetprocessing timer 242 operates in the order of milliseconds, such as forexample 100 ms, 50 ms or 25 ms. For example, in some embodiments, thepacket processing timer 242 provides time intervals or otherwise causesa network packet to be processed by the high speed layer 2-7 integratedpacket engine 240 at a 10 ms time interval, while in other embodiments,at a 5 ms time interval, and still yet in further embodiments, as shortas a 3, 2, or 1 ms time interval. The high speed layer 2-7 integratedpacket engine 240 may be interfaced, integrated or in communication withthe encryption engine 234, cache manager 232, policy engine 236 andmulti-protocol compression engine 238 during operation. As such, any ofthe logic, functions, or operations of the encryption engine 234, cachemanager 232, policy engine 236 and multi-protocol compression logic 238may be performed responsive to the packet processing timer 242 and/orthe packet engine 240. Therefore, any of the logic, functions, oroperations of the encryption engine 234, cache manager 232, policyengine 236 and multi-protocol compression logic 238 may be performed atthe granularity of time intervals provided via the packet processingtimer 242, for example, at a time interval of less than or equal to 10ms. For example, in one embodiment, the cache manager 232 may performinvalidation of any cached objects responsive to the high speed layer2-7 integrated packet engine 240 and/or the packet processing timer 242.In another embodiment, the expiry or invalidation time of a cachedobject can be set to the same order of granularity as the time intervalof the packet processing timer 242, such as at every 10 ms.

In contrast to kernel space 204, user space 202 is the memory area orportion of the operating system used by user mode applications orprograms otherwise running in user mode. A user mode application may notaccess kernel space 204 directly and uses service calls in order toaccess kernel services. As shown in FIG. 2, user space 202 of appliance200 includes a graphical user interface (GUI) 210, a command lineinterface (CLI) 212, shell services 214, health monitoring program 216,and daemon services 218. GUI 210 and CLI 212 provide a means by which asystem administrator or other user can interact with and control theoperation of appliance 200, such as via the operating system of theappliance 200. The GUI 210 or CLI 212 can comprise code running in userspace 202 or kernel space 204. The GUI 210 may be any type and form ofgraphical user interface and may be presented via text, graphical orotherwise, by any type of program or application, such as a browser. TheCLI 212 may be any type and form of command line or text-basedinterface, such as a command line provided by the operating system. Forexample, the CLI 212 may comprise a shell, which is a tool to enableusers to interact with the operating system. In some embodiments, theCLI 212 may be provided via a bash, csh, tcsh, or ksh type shell. Theshell services 214 comprises the programs, services, tasks, processes orexecutable instructions to support interaction with the appliance 200 oroperating system by a user via the GUI 210 and/or CLI 212.

Health monitoring program 216 is used to monitor, check, report andensure that network systems are functioning properly and that users arereceiving requested content over a network. Health monitoring program216 comprises one or more programs, services, tasks, processes orexecutable instructions to provide logic, rules, functions or operationsfor monitoring any activity of the appliance 200. In some embodiments,the health monitoring program 216 intercepts and inspects any networktraffic passed via the appliance 200. In other embodiments, the healthmonitoring program 216 interfaces by any suitable means and/ormechanisms with one or more of the following: the encryption engine 234,cache manager 232, policy engine 236, multi-protocol compression logic238, packet engine 240, daemon services 218, and shell services 214. Assuch, the health monitoring program 216 may call any applicationprogramming interface (API) to determine a state, status, or health ofany portion of the appliance 200. For example, the health monitoringprogram 216 may ping or send a status inquiry on a periodic basis tocheck if a program, process, service or task is active and currentlyrunning. In another example, the health monitoring program 216 may checkany status, error or history logs provided by any program, process,service or task to determine any condition, status or error with anyportion of the appliance 200.

Daemon services 218 are programs that run continuously or in thebackground and handle periodic service requests received by appliance200. In some embodiments, a daemon service may forward the requests toother programs or processes, such as another daemon service 218 asappropriate. As known to those skilled in the art, a daemon service 218may run unattended to perform continuous or periodic system widefunctions, such as network control, or to perform any desired task. Insome embodiments, one or more daemon services 218 run in the user space202, while in other embodiments, one or more daemon services 218 run inthe kernel space.

Referring now to FIG. 2B, another embodiment of the appliance 200 isdepicted. In brief overview, the appliance 200 provides one or more ofthe following services, functionality or operations: SSL VPNconnectivity 280, switching/load balancing 284, Domain Name Serviceresolution 286, acceleration 288 and an application firewall 290 forcommunications between one or more clients 102 and one or more servers106. Each of the servers 106 may provide one or more network relatedservices 270 a-270 n (referred to as services 270). For example, aserver 106 may provide an http service 270. The appliance 200 comprisesone or more virtual servers or virtual internet protocol servers,referred to as a vServer, VIP server, or just VIP 275 a-275 n (alsoreferred herein as vServer 275). The vServer 275 receives, intercepts orotherwise processes communications between a client 102 and a server 106in accordance with the configuration and operations of the appliance200.

The vServer 275 may comprise software, hardware or any combination ofsoftware and hardware. The vServer 275 may comprise any type and form ofprogram, service, task, process or executable instructions operating inuser mode 202, kernel mode 204 or any combination thereof in theappliance 200. The vServer 275 includes any logic, functions, rules, oroperations to perform any embodiments of the techniques describedherein, such as SSL VPN 280, switching/load balancing 284, Domain NameService resolution 286, acceleration 288 and an application firewall290. In some embodiments, the vServer 275 establishes a connection to aservice 270 of a server 106. The service 275 may comprise any program,application, process, task or set of executable instructions capable ofconnecting to and communicating to the appliance 200, client 102 orvServer 275. For example, the service 275 may comprise a web server,http server, ftp, email or database server. In some embodiments, theservice 270 is a daemon process or network driver for listening,receiving and/or sending communications for an application, such asemail, database or an enterprise application. In some embodiments, theservice 270 may communicate on a specific IP address, or IP address andport.

In some embodiments, the vServer 275 applies one or more policies of thepolicy engine 236 to network communications between the client 102 andserver 106. In one embodiment, the policies are associated with avServer 275. In another embodiment, the policies are based on a user, ora group of users. In yet another embodiment, a policy is global andapplies to one or more vServers 275 a-275 n, and any user or group ofusers communicating via the appliance 200. In some embodiments, thepolicies of the policy engine have conditions upon which the policy isapplied based on any content of the communication, such as internetprotocol address, port, protocol type, header or fields in a packet, orthe context of the communication, such as user, group of the user,vServer 275, transport layer connection, and/or identification orattributes of the client 102 or server 106.

In other embodiments, the appliance 200 communicates or interfaces withthe policy engine 236 to determine authentication and/or authorizationof a remote user or a remote client 102 to access the computingenvironment 15, application, and/or data file from a server 106. Inanother embodiment, the appliance 200 communicates or interfaces withthe policy engine 236 to determine authentication and/or authorizationof a remote user or a remote client 102 to have the application deliverysystem 190 deliver one or more of the computing environment 15,application, and/or data file. In yet another embodiment, the appliance200 establishes a VPN or SSL VPN connection based on the policy engine's236 authentication and/or authorization of a remote user or a remoteclient 102 In one embodiment, the appliance 200 controls the flow ofnetwork traffic and communication sessions based on policies of thepolicy engine 236. For example, the appliance 200 may control the accessto a computing environment 15, application or data file based on thepolicy engine 236.

In some embodiments, the vServer 275 establishes a transport layerconnection, such as a TCP or UDP connection with a client 102 via theclient agent 120. In one embodiment, the vServer 275 listens for andreceives communications from the client 102. In other embodiments, thevServer 275 establishes a transport layer connection, such as a TCP orUDP connection with a client server 106. In one embodiment, the vServer275 establishes the transport layer connection to an internet protocoladdress and port of a server 270 running on the server 106. In anotherembodiment, the vServer 275 associates a first transport layerconnection to a client 102 with a second transport layer connection tothe server 106. In some embodiments, a vServer 275 establishes a pool oftransport layer connections to a server 106 and multiplexes clientrequests via the pooled transport layer connections.

In some embodiments, the appliance 200 provides a SSL VPN connection 280between a client 102 and a server 106. For example, a client 102 on afirst network 102 requests to establish a connection to a server 106 ona second network 104′. In some embodiments, the second network 104′ isnot routable from the first network 104. In other embodiments, theclient 102 is on a public network 104 and the server 106 is on a privatenetwork 104′, such as a corporate network. In one embodiment, the clientagent 120 intercepts communications of the client 102 on the firstnetwork 104, encrypts the communications, and transmits thecommunications via a first transport layer connection to the appliance200. The appliance 200 associates the first transport layer connectionon the first network 104 to a second transport layer connection to theserver 106 on the second network 104. The appliance 200 receives theintercepted communication from the client agent 102, decrypts thecommunications, and transmits the communication to the server 106 on thesecond network 104 via the second transport layer connection. The secondtransport layer connection may be a pooled transport layer connection.As such, the appliance 200 provides an end-to-end secure transport layerconnection for the client 102 between the two networks 104, 104′.

In one embodiment, the appliance 200 hosts an intranet internet protocolor IntranetIP 282 address of the client 102 on the virtual privatenetwork 104. The client 102 has a local network identifier, such as aninternet protocol (IP) address and/or host name on the first network104. When connected to the second network 104′ via the appliance 200,the appliance 200 establishes, assigns or otherwise provides anIntranetIP address 282, which is a network identifier, such as IPaddress and/or host name, for the client 102 on the second network 104′.The appliance 200 listens for and receives on the second or privatenetwork 104′ for any communications directed towards the client 102using the client's established IntranetIP 282. In one embodiment, theappliance 200 acts as or on behalf of the client 102 on the secondprivate network 104. For example, in another embodiment, a vServer 275listens for and responds to communications to the IntranetIP 282 of theclient 102. In some embodiments, if a computing device 100 on the secondnetwork 104′ transmits a request, the appliance 200 processes therequest as if it were the client 102. For example, the appliance 200 mayrespond to a ping to the client's IntranetIP 282. In another example,the appliance may establish a connection, such as a TCP or UDPconnection, with computing device 100 on the second network 104requesting a connection with the client's IntranetIP 282.

In some embodiments, the appliance 200 provides one or more of thefollowing acceleration techniques 288 to communications between theclient 102 and server 106: 1) compression; 2) decompression; 3)Transmission Control Protocol pooling; 4) Transmission Control Protocolmultiplexing; 5) Transmission Control Protocol buffering; and 6)caching. In one embodiment, the appliance 200 relieves servers 106 ofmuch of the processing load caused by repeatedly opening and closingtransport layers connections to clients 102 by opening one or moretransport layer connections with each server 106 and maintaining theseconnections to allow repeated data accesses by clients via the Internet.This technique is referred to herein as “connection pooling”.

In some embodiments, in order to seamlessly splice communications from aclient 102 to a server 106 via a pooled transport layer connection, theappliance 200 translates or multiplexes communications by modifyingsequence number and acknowledgment numbers at the transport layerprotocol level. This is referred to as “connection multiplexing”. Insome embodiments, no application layer protocol interaction is required.For example, in the case of an in-bound packet (that is, a packetreceived from a client 102), the source network address of the packet ischanged to that of an output port of appliance 200, and the destinationnetwork address is changed to that of the intended server. In the caseof an outbound packet (that is, one received from a server 106), thesource network address is changed from that of the server 106 to that ofan output port of appliance 200 and the destination address is changedfrom that of appliance 200 to that of the requesting client 102. Thesequence numbers and acknowledgment numbers of the packet are alsotranslated to sequence numbers and acknowledgement numbers expected bythe client 102 on the appliance's 200 transport layer connection to theclient 102. In some embodiments, the packet checksum of the transportlayer protocol is recalculated to account for these translations.

In another embodiment, the appliance 200 provides switching orload-balancing functionality 284 for communications between the client102 and server 106. In some embodiments, the appliance 200 distributestraffic and directs client requests to a server 106 based on layer 4 orapplication-layer request data. In one embodiment, although the networklayer or layer 2 of the network packet identifies a destination server106, the appliance 200 determines the server 106 to distribute thenetwork packet by application information and data carried as payload ofthe transport layer packet. In one embodiment, the health monitoringprograms 216 of the appliance 200 monitor the health of servers todetermine the server 106 for which to distribute a client's request. Insome embodiments, if the appliance 200 detects a server 106 is notavailable or has a load over a predetermined threshold, the appliance200 can direct or distribute client requests to another server 106.

In some embodiments, the appliance 200 acts as a Domain Name Service(DNS) resolver or otherwise provides resolution of a DNS request fromclients 102. In some embodiments, the appliance intercepts a DNS requesttransmitted by the client 102. In one embodiment, the appliance 200responds to a client's DNS request with an IP address of or hosted bythe appliance 200. In this embodiment, the client 102 transmits networkcommunication for the domain name to the appliance 200. In anotherembodiment, the appliance 200 responds to a client's DNS request with anIP address of or hosted by a second appliance 200′. In some embodiments,the appliance 200 responds to a client's DNS request with an IP addressof a server 106 determined by the appliance 200.

In yet another embodiment, the appliance 200 provides applicationfirewall functionality 290 for communications between the client 102 andserver 106. In one embodiment, the policy engine 236 provides rules fordetecting and blocking illegitimate requests. In some embodiments, theapplication firewall 290 protects against denial of service (DoS)attacks. In other embodiments, the appliance inspects the content ofintercepted requests to identify and block application-based attacks. Insome embodiments, the rules/policy engine 236 comprises one or moreapplication firewall or security control policies for providingprotections against various classes and types of web or Internet basedvulnerabilities, such as one or more of the following: 1) bufferoverflow, 2) CGI-BIN parameter manipulation, 3) form/hidden fieldmanipulation, 4) forceful browsing, 5) cookie or session poisoning, 6)broken access control list (ACLs) or weak passwords, 7) cross-sitescripting (XSS), 8) command injection, 9) SQL injection, 10) errortriggering sensitive information leak, 11) insecure use of cryptography,12) server misconfiguration, 13) back doors and debug options, 14)website defacement, 15) platform or operating systems vulnerabilities,and 16) zero-day exploits. In an embodiment, the application firewall290 provides HTML form field protection in the form of inspecting oranalyzing the network communication for one or more of the following: 1)required fields are returned, 2) no added field allowed, 3) read-onlyand hidden field enforcement, 4) drop-down list and radio button fieldconformance, and 5) form-field max-length enforcement. In someembodiments, the application firewall 290 ensures cookies are notmodified. In other embodiments, the application firewall 290 protectsagainst forceful browsing by enforcing legal URLs.

In still yet other embodiments, the application firewall 290 protectsany confidential information contained in the network communication. Theapplication firewall 290 may inspect or analyze any networkcommunication in accordance with the rules or polices of the engine 236to identify any confidential information in any field of the networkpacket. In some embodiments, the application firewall 290 identifies inthe network communication one or more occurrences of a credit cardnumber, password, social security number, name, patient code, contactinformation, and age. The encoded portion of the network communicationmay comprise these occurrences or the confidential information. Based onthese occurrences, in one embodiment, the application firewall 290 maytake a policy action on the network communication, such as preventtransmission of the network communication. In another embodiment, theapplication firewall 290 may rewrite, remove or otherwise mask suchidentified occurrence or confidential information.

Still referring to FIG. 2B, the appliance 200 may include a performancemonitoring agent 197 as discussed above in conjunction with FIG. 1D. Inone embodiment, the appliance 200 receives the monitoring agent 197 fromthe monitoring service 198 or monitoring server 106 as depicted in FIG.1D. In some embodiments, the appliance 200 stores the monitoring agent197 in storage, such as disk, for delivery to any client or server incommunication with the appliance 200. For example, in one embodiment,the appliance 200 transmits the monitoring agent 197 to a client uponreceiving a request to establish a transport layer connection. In otherembodiments, the appliance 200 transmits the monitoring agent 197 uponestablishing the transport layer connection with the client 102. Inanother embodiment, the appliance 200 transmits the monitoring agent 197to the client upon intercepting or detecting a request for a web page.In yet another embodiment, the appliance 200 transmits the monitoringagent 197 to a client or a server in response to a request from themonitoring server 198. In one embodiment, the appliance 200 transmitsthe monitoring agent 197 to a second appliance 200′ or appliance 205.

In other embodiments, the appliance 200 executes the monitoring agent197. In one embodiment, the monitoring agent 197 measures and monitorsthe performance of any application, program, process, service, task orthread executing on the appliance 200. For example, the monitoring agent197 may monitor and measure performance and operation of vServers275A-275N. In another embodiment, the monitoring agent 197 measures andmonitors the performance of any transport layer connections of theappliance 200. In some embodiments, the monitoring agent 197 measuresand monitors the performance of any user sessions traversing theappliance 200. In one embodiment, the monitoring agent 197 measures andmonitors the performance of any virtual private network connectionsand/or sessions traversing the appliance 200, such an SSL VPN session.In still further embodiments, the monitoring agent 197 measures andmonitors the memory, CPU and disk usage and performance of the appliance200. In yet another embodiment, the monitoring agent 197 measures andmonitors the performance of any acceleration technique 288 performed bythe appliance 200, such as SSL offloading, connection pooling andmultiplexing, caching, and compression. In some embodiments, themonitoring agent 197 measures and monitors the performance of any loadbalancing and/or content switching 284 performed by the appliance 200.In other embodiments, the monitoring agent 197 measures and monitors theperformance of application firewall 290 protection and processingperformed by the appliance 200.

C. Client Agent

Referring now to FIG. 3, an embodiment of the client agent 120 isdepicted. The client 102 includes a client agent 120 for establishingand exchanging communications with the appliance 200 and/or server 106via a network 104. In brief overview, the client 102 operates oncomputing device 100 having an operating system with a kernel mode 302and a user mode 303, and a network stack 310 with one or more layers 310a-310 b. The client 102 may have installed and/or execute one or moreapplications. In some embodiments, one or more applications maycommunicate via the network stack 310 to a network 104. One of theapplications, such as a web browser, may also include a first program322. For example, the first program 322 may be used in some embodimentsto install and/or execute the client agent 120, or any portion thereof.The client agent 120 includes an interception mechanism, or interceptor350, for intercepting network communications from the network stack 310from the one or more applications.

The network stack 310 of the client 102 may comprise any type and formof software, or hardware, or any combinations thereof, for providingconnectivity to and communications with a network. In one embodiment,the network stack 310 comprises a software implementation for a networkprotocol suite. The network stack 310 may comprise one or more networklayers, such as any networks layers of the Open Systems Interconnection(OSI) communications model as those skilled in the art recognize andappreciate. As such, the network stack 310 may comprise any type andform of protocols for any of the following layers of the OSI model: 1)physical link layer, 2) data link layer, 3) network layer, 4) transportlayer, 5) session layer, 6) presentation layer, and 7) applicationlayer. In one embodiment, the network stack 310 may comprise a transportcontrol protocol (TCP) over the network layer protocol of the internetprotocol (IP), generally referred to as TCP/IP. In some embodiments, theTCP/IP protocol may be carried over the Ethernet protocol, which maycomprise any of the family of IEEE wide-area-network (WAN) orlocal-area-network (LAN) protocols, such as those protocols covered bythe IEEE 802.3. In some embodiments, the network stack 310 comprises anytype and form of a wireless protocol, such as IEEE 802.11 and/or mobileinternet protocol.

In view of a TCP/IP based network, any TCP/IP based protocol may beused, including Messaging Application Programming Interface (MAPI)(email), File Transfer Protocol (FTP), HyperText Transfer Protocol(HTTP), Common Internet File System (CIFS) protocol (file transfer),Independent Computing Architecture (ICA) protocol, Remote DesktopProtocol (RDP), Wireless Application Protocol (WAP), Mobile IP protocol,and Voice Over IP (VoIP) protocol. In another embodiment, the networkstack 310 comprises any type and form of transport control protocol,such as a modified transport control protocol, for example a TransactionTCP (T/TCP), TCP with selection acknowledgements (TCP-SACK), TCP withlarge windows (TCP-LW), a congestion prediction protocol such as theTCP-Vegas protocol, and a TCP spoofing protocol. In other embodiments,any type and form of user datagram protocol (UDP), such as UDP over IP,may be used by the network stack 310, such as for voice communicationsor real-time data communications.

Furthermore, the network stack 310 may include one or more networkdrivers supporting the one or more layers, such as a TCP driver or anetwork layer driver. The network drivers may be included as part of theoperating system of the computing device 100 or as part of any networkinterface cards or other network access components of the computingdevice 100. In some embodiments, any of the network drivers of thenetwork stack 310 may be customized, modified or adapted to provide acustom or modified portion of the network stack 310 in support of any ofthe techniques described herein. In other embodiments, the accelerationprogram 302 is designed and constructed to operate with or work inconjunction with the network stack 310 installed or otherwise providedby the operating system of the client 102.

The network stack 310 comprises any type and form of interfaces forreceiving, obtaining, providing or otherwise accessing any informationand data related to network communications of the client 102. In oneembodiment, an interface to the network stack 310 comprises anapplication programming interface (API). The interface may also compriseany function call, hooking or filtering mechanism, event or call backmechanism, or any type of interfacing technique. The network stack 310via the interface may receive or provide any type and form of datastructure, such as an object, related to functionality or operation ofthe network stack 310. For example, the data structure may compriseinformation and data related to a network packet or one or more networkpackets. In some embodiments, the data structure comprises a portion ofthe network packet processed at a protocol layer of the network stack310, such as a network packet of the transport layer. In someembodiments, the data structure 325 comprises a kernel-level datastructure, while in other embodiments, the data structure 325 comprisesa user-mode data structure. A kernel-level data structure may comprise adata structure obtained or related to a portion of the network stack 310operating in kernel-mode 302, or a network driver or other softwarerunning in kernel-mode 302, or any data structure obtained or receivedby a service, process, task, thread or other executable instructionsrunning or operating in kernel-mode of the operating system.

Additionally, some portions of the network stack 310 may execute oroperate in kernel-mode 302, for example, the data link or network layer,while other portions execute or operate in user-mode 303, such as anapplication layer of the network stack 310. For example, a first portion310 a of the network stack may provide user-mode access to the networkstack 310 to an application while a second portion 310 a of the networkstack 310 provides access to a network. In some embodiments, a firstportion 310 a of the network stack may comprise one or more upper layersof the network stack 310, such as any of layers 5-7. In otherembodiments, a second portion 310 b of the network stack 310 comprisesone or more lower layers, such as any of layers 1-4. Each of the firstportion 310 a and second portion 310 b of the network stack 310 maycomprise any portion of the network stack 310, at any one or morenetwork layers, in user-mode 203, kernel-mode, 202, or combinationsthereof, or at any portion of a network layer or interface point to anetwork layer or any portion of or interface point to the user-mode 203and kernel-mode 203.

The interceptor 350 may comprise software, hardware, or any combinationof software and hardware. In one embodiment, the interceptor 350intercept a network communication at any point in the network stack 310,and redirects or transmits the network communication to a destinationdesired, managed or controlled by the interceptor 350 or client agent120. For example, the interceptor 350 may intercept a networkcommunication of a network stack 310 of a first network and transmit thenetwork communication to the appliance 200 for transmission on a secondnetwork 104. In some embodiments, the interceptor 350 comprises any typeinterceptor 350 comprises a driver, such as a network driver constructedand designed to interface and work with the network stack 310. In someembodiments, the client agent 120 and/or interceptor 350 operates at oneor more layers of the network stack 310, such as at the transport layer.In one embodiment, the interceptor 350 comprises a filter driver,hooking mechanism, or any form and type of suitable network driverinterface that interfaces to the transport layer of the network stack,such as via the transport driver interface (TDI). In some embodiments,the interceptor 350 interfaces to a first protocol layer, such as thetransport layer and another protocol layer, such as any layer above thetransport protocol layer, for example, an application protocol layer. Inone embodiment, the interceptor 350 may comprise a driver complying withthe Network Driver Interface Specification (NDIS), or a NDIS driver. Inanother embodiment, the interceptor 350 may comprise a mini-filter or amini-port driver. In one embodiment, the interceptor 350, or portionthereof, operates in kernel-mode 202. In another embodiment, theinterceptor 350, or portion thereof, operates in user-mode 203. In someembodiments, a portion of the interceptor 350 operates in kernel-mode202 while another portion of the interceptor 350 operates in user-mode203. In other embodiments, the client agent 120 operates in user-mode203 but interfaces via the interceptor 350 to a kernel-mode driver,process, service, task or portion of the operating system, such as toobtain a kernel-level data structure 225. In further embodiments, theinterceptor 350 is a user-mode application or program, such asapplication.

In one embodiment, the interceptor 350 intercepts any transport layerconnection requests. In these embodiments, the interceptor 350 executetransport layer application programming interface (API) calls to set thedestination information, such as destination IP address and/or port to adesired location for the location. In this manner, the interceptor 350intercepts and redirects the transport layer connection to a IP addressand port controlled or managed by the interceptor 350 or client agent120. In one embodiment, the interceptor 350 sets the destinationinformation for the connection to a local IP address and port of theclient 102 on which the client agent 120 is listening. For example, theclient agent 120 may comprise a proxy service listening on a local IPaddress and port for redirected transport layer communications. In someembodiments, the client agent 120 then communicates the redirectedtransport layer communication to the appliance 200.

In some embodiments, the interceptor 350 intercepts a Domain NameService (DNS) request. In one embodiment, the client agent 120 and/orinterceptor 350 resolves the DNS request. In another embodiment, theinterceptor transmits the intercepted DNS request to the appliance 200for DNS resolution. In one embodiment, the appliance 200 resolves theDNS request and communicates the DNS response to the client agent 120.In some embodiments, the appliance 200 resolves the DNS request viaanother appliance 200′ or a DNS server 106.

In yet another embodiment, the client agent 120 may comprise two agents120 and 120′. In one embodiment, a first agent 120 may comprise aninterceptor 350 operating at the network layer of the network stack 310.In some embodiments, the first agent 120 intercepts network layerrequests such as Internet Control Message Protocol (ICMP) requests(e.g., ping and traceroute). In other embodiments, the second agent 120′may operate at the transport layer and intercept transport layercommunications. In some embodiments, the first agent 120 interceptscommunications at one layer of the network stack 210 and interfaces withor communicates the intercepted communication to the second agent 120′.

The client agent 120 and/or interceptor 350 may operate at or interfacewith a protocol layer in a manner transparent to any other protocollayer of the network stack 310. For example, in one embodiment, theinterceptor 350 operates or interfaces with the transport layer of thenetwork stack 310 transparently to any protocol layer below thetransport layer, such as the network layer, and any protocol layer abovethe transport layer, such as the session, presentation or applicationlayer protocols. This allows the other protocol layers of the networkstack 310 to operate as desired and without modification for using theinterceptor 350. As such, the client agent 120 and/or interceptor 350can interface with the transport layer to secure, optimize, accelerate,route or load-balance any communications provided via any protocolcarried by the transport layer, such as any application layer protocolover TCP/IP.

Furthermore, the client agent 120 and/or interceptor may operate at orinterface with the network stack 310 in a manner transparent to anyapplication, a user of the client 102, and any other computing device,such as a server, in communications with the client 102. The clientagent 120 and/or interceptor 350 may be installed and/or executed on theclient 102 in a manner without modification of an application. In someembodiments, the user of the client 102 or a computing device incommunications with the client 102 are not aware of the existence,execution or operation of the client agent 120 and/or interceptor 350.As such, in some embodiments, the client agent 120 and/or interceptor350 is installed, executed, and/or operated transparently to anapplication, user of the client 102, another computing device, such as aserver, or any of the protocol layers above and/or below the protocollayer interfaced to by the interceptor 350.

The client agent 120 includes an acceleration program 302, a streamingclient 306, a collection agent 304, and/or monitoring agent 197. In oneembodiment, the client agent 120 comprises an Independent ComputingArchitecture (ICA) client, or any portion thereof, developed by CitrixSystems, Inc. of Fort Lauderdale, Fla., and is also referred to as anICA client. In some embodiments, the client 120 comprises an applicationstreaming client 306 for streaming an application from a server 106 to aclient 102. In some embodiments, the client agent 120 comprises anacceleration program 302 for accelerating communications between client102 and server 106. In another embodiment, the client agent 120 includesa collection agent 304 for performing end-point detection/scanning andcollecting end-point information for the appliance 200 and/or server106.

In some embodiments, the acceleration program 302 comprises aclient-side acceleration program for performing one or more accelerationtechniques to accelerate, enhance or otherwise improve a client'scommunications with and/or access to a server 106, such as accessing anapplication provided by a server 106. The logic, functions, and/oroperations of the executable instructions of the acceleration program302 may perform one or more of the following acceleration techniques: 1)multi-protocol compression, 2) transport control protocol pooling, 3)transport control protocol multiplexing, 4) transport control protocolbuffering, and 5) caching via a cache manager. Additionally, theacceleration program 302 may perform encryption and/or decryption of anycommunications received and/or transmitted by the client 102. In someembodiments, the acceleration program 302 performs one or more of theacceleration techniques in an integrated manner or fashion.Additionally, the acceleration program 302 can perform compression onany of the protocols, or multiple-protocols, carried as a payload of anetwork packet of the transport layer protocol.

The streaming client 306 comprises an application, program, process,service, task or executable instructions for receiving and executing astreamed application from a server 106. A server 106 may stream one ormore application data files to the streaming client 306 for playing,executing or otherwise causing to be executed the application on theclient 102. In some embodiments, the server 106 transmits a set ofcompressed or packaged application data files to the streaming client306. In some embodiments, the plurality of application files arecompressed and stored on a file server within an archive file such as aCAB, ZIP, SIT, TAR, JAR or other archive. In one embodiment, the server106 decompresses, unpackages or unarchives the application files andtransmits the files to the client 102. In another embodiment, the client102 decompresses, unpackages or unarchives the application files. Thestreaming client 306 dynamically installs the application, or portionthereof, and executes the application. In one embodiment, the streamingclient 306 may be an executable program. In some embodiments, thestreaming client 306 may be able to launch another executable program.

The collection agent 304 comprises an application, program, process,service, task or executable instructions for identifying, obtainingand/or collecting information about the client 102. In some embodiments,the appliance 200 transmits the collection agent 304 to the client 102or client agent 120. The collection agent 304 may be configuredaccording to one or more policies of the policy engine 236 of theappliance. In other embodiments, the collection agent 304 transmitscollected information on the client 102 to the appliance 200. In oneembodiment, the policy engine 236 of the appliance 200 uses thecollected information to determine and provide access, authenticationand authorization control of the client's connection to a network 104.

In one embodiment, the collection agent 304 comprises an end-pointdetection and scanning mechanism, which identifies and determines one ormore attributes or characteristics of the client. For example, thecollection agent 304 may identify and determine any one or more of thefollowing client-side attributes: 1) the operating system an/or aversion of an operating system, 2) a service pack of the operatingsystem, 3) a running service, 4) a running process, and 5) a file. Thecollection agent 304 may also identify and determine the presence orversions of any one or more of the following on the client: 1) antivirussoftware, 2) personal firewall software, 3) anti-spam software, and 4)internet security software. The policy engine 236 may have one or morepolicies based on any one or more of the attributes or characteristicsof the client or client-side attributes.

In some embodiments, the client agent 120 includes a monitoring agent197 as discussed in conjunction with FIGS. 1D and 2B. The monitoringagent 197 may be any type and form of script, such as Visual Basic orJava script. In one embodiment, the monitoring agent 197 monitors andmeasures performance of any portion of the client agent 120. Forexample, in some embodiments, the monitoring agent 197 monitors andmeasures performance of the acceleration program 302. In anotherembodiment, the monitoring agent 197 monitors and measures performanceof the streaming client 306. In other embodiments, the monitoring agent197 monitors and measures performance of the collection agent 304. Instill another embodiment, the monitoring agent 197 monitors and measuresperformance of the interceptor 350. In some embodiments, the monitoringagent 197 monitors and measures any resource of the client 102, such asmemory, CPU and disk.

The monitoring agent 197 may monitor and measure performance of anyapplication of the client. In one embodiment, the monitoring agent 197monitors and measures performance of a browser on the client 102. Insome embodiments, the monitoring agent 197 monitors and measuresperformance of any application delivered via the client agent 120. Inother embodiments, the monitoring agent 197 measures and monitors enduser response times for an application, such as web-based or HTTPresponse times. The monitoring agent 197 may monitor and measureperformance of an ICA or RDP client. In another embodiment, themonitoring agent 197 measures and monitors metrics for a user session orapplication session. In some embodiments, monitoring agent 197 measuresand monitors an ICA or RDP session. In one embodiment, the monitoringagent 197 measures and monitors the performance of the appliance 200 inaccelerating delivery of an application and/or data to the client 102.

In some embodiments and still referring to FIG. 3, a first program 322may be used to install and/or execute the client agent 120, or portionthereof, such as the interceptor 350, automatically, silently,transparently, or otherwise. In one embodiment, the first program 322comprises a plugin component, such an ActiveX control or Java control orscript that is loaded into and executed by an application. For example,the first program comprises an ActiveX control loaded and run by a webbrowser application, such as in the memory space or context of theapplication. In another embodiment, the first program 322 comprises aset of executable instructions loaded into and run by the application,such as a browser. In one embodiment, the first program 322 comprises adesigned and constructed program to install the client agent 120. Insome embodiments, the first program 322 obtains, downloads, or receivesthe client agent 120 via the network from another computing device. Inanother embodiment, the first program 322 is an installer program or aplug and play manager for installing programs, such as network drivers,on the operating system of the client 102.

D. Systems and Methods for Providing Virtualized Application DeliveryController

Referring now to FIG. 4A, a block diagram depicts one embodiment of avirtualization environment 400. In brief overview, a computing device100 includes a hypervisor layer, a virtualization layer, and a hardwarelayer. The hypervisor layer includes a hypervisor 401 (also referred toas a virtualization manager) that allocates and manages access to anumber of physical resources in the hardware layer (e.g., theprocessor(s) 421, and disk(s) 428) by at least one virtual machineexecuting in the virtualization layer. The virtualization layer includesat least one operating system 410 and a plurality of virtual resourcesallocated to the at least one operating system 410. Virtual resourcesmay include, without limitation, a plurality of virtual processors 432a, 432 b, 432 c (generally 432), and virtual disks 442 a, 442 b, 442 c(generally 442), as well as virtual resources such as virtual memory andvirtual network interfaces. The plurality of virtual resources and theoperating system 410 may be referred to as a virtual machine 406. Avirtual machine 406 may include a control operating system 405 incommunication with the hypervisor 401 and used to execute applicationsfor managing and configuring other virtual machines on the computingdevice 100.

In greater detail, a hypervisor 401 may provide virtual resources to anoperating system in any manner which simulates the operating systemhaving access to a physical device. A hypervisor 401 may provide virtualresources to any number of guest operating systems 410 a, 410 b(generally 410). In some embodiments, a computing device 100 executesone or more types of hypervisors. In these embodiments, hypervisors maybe used to emulate virtual hardware, partition physical hardware,virtualize physical hardware, and execute virtual machines that provideaccess to computing environments. Hypervisors may include thosemanufactured by VMWare, Inc., of Palo Alto, Calif.; the XEN hypervisor,an open source product whose development is overseen by the open sourceXen.org community; HyperV, VirtualServer or virtual PC hypervisorsprovided by Microsoft, or others. In some embodiments, a computingdevice 100 executing a hypervisor that creates a virtual machineplatform on which guest operating systems may execute is referred to asa host server. In one of these embodiments, for example, the computingdevice 100 is a XEN SERVER provided by Citrix Systems, Inc., of FortLauderdale, Fla.

In some embodiments, a hypervisor 401 executes within an operatingsystem executing on a computing device. In one of these embodiments, acomputing device executing an operating system and a hypervisor 401 maybe said to have a host operating system (the operating system executingon the computing device), and a guest operating system (an operatingsystem executing within a computing resource partition provided by thehypervisor 401). In other embodiments, a hypervisor 401 interactsdirectly with hardware on a computing device, instead of executing on ahost operating system. In one of these embodiments, the hypervisor 401may be said to be executing on “bare metal,” referring to the hardwarecomprising the computing device.

In some embodiments, a hypervisor 401 may create a virtual machine 406a-c (generally 406) in which an operating system 410 executes. In one ofthese embodiments, for example, the hypervisor 401 loads a virtualmachine image to create a virtual machine 406. In another of theseembodiments, the hypervisor 401 executes an operating system 410 withinthe virtual machine 406. In still another of these embodiments, thevirtual machine 406 executes an operating system 410.

In some embodiments, the hypervisor 401 controls processor schedulingand memory partitioning for a virtual machine 406 executing on thecomputing device 100. In one of these embodiments, the hypervisor 401controls the execution of at least one virtual machine 406. In anotherof these embodiments, the hypervisor 401 presents at least one virtualmachine 406 with an abstraction of at least one hardware resourceprovided by the computing device 100. In other embodiments, thehypervisor 401 controls whether and how physical processor capabilitiesare presented to the virtual machine 406.

A control operating system 405 may execute at least one application formanaging and configuring the guest operating systems. In one embodiment,the control operating system 405 may execute an administrativeapplication, such as an application including a user interface providingadministrators with access to functionality for managing the executionof a virtual machine, including functionality for executing a virtualmachine, terminating an execution of a virtual machine, or identifying atype of physical resource for allocation to the virtual machine. Inanother embodiment, the hypervisor 401 executes the control operatingsystem 405 within a virtual machine 406 created by the hypervisor 401.In still another embodiment, the control operating system 405 executesin a virtual machine 406 that is authorized to directly access physicalresources on the computing device 100. In some embodiments, a controloperating system 405 a on a computing device 100 a may exchange datawith a control operating system 405 b on a computing device 100 b, viacommunications between a hypervisor 401 a and a hypervisor 401 b. Inthis way, one or more computing devices 100 may exchange data with oneor more of the other computing devices 100 regarding processors andother physical resources available in a pool of resources. In one ofthese embodiments, this functionality allows a hypervisor to manage apool of resources distributed across a plurality of physical computingdevices. In another of these embodiments, multiple hypervisors manageone or more of the guest operating systems executed on one of thecomputing devices 100.

In one embodiment, the control operating system 405 executes in avirtual machine 406 that is authorized to interact with at least oneguest operating system 410. In another embodiment, a guest operatingsystem 410 communicates with the control operating system 405 via thehypervisor 401 in order to request access to a disk or a network. Instill another embodiment, the guest operating system 410 and the controloperating system 405 may communicate via a communication channelestablished by the hypervisor 401, such as, for example, via a pluralityof shared memory pages made available by the hypervisor 401.

In some embodiments, the control operating system 405 includes a networkback-end driver for communicating directly with networking hardwareprovided by the computing device 100. In one of these embodiments, thenetwork back-end driver processes at least one virtual machine requestfrom at least one guest operating system 110. In other embodiments, thecontrol operating system 405 includes a block back-end driver forcommunicating with a storage element on the computing device 100. In oneof these embodiments, the block back-end driver reads and writes datafrom the storage element based upon at least one request received from aguest operating system 410.

In one embodiment, the control operating system 405 includes a toolsstack 404. In another embodiment, a tools stack 404 providesfunctionality for interacting with the hypervisor 401, communicatingwith other control operating systems 405 (for example, on a secondcomputing device 100 b), or managing virtual machines 406 b, 406 c onthe computing device 100. In another embodiment, the tools stack 404includes customized applications for providing improved managementfunctionality to an administrator of a virtual machine farm. In someembodiments, at least one of the tools stack 404 and the controloperating system 405 include a management API that provides an interfacefor remotely configuring and controlling virtual machines 406 running ona computing device 100. In other embodiments, the control operatingsystem 405 communicates with the hypervisor 401 through the tools stack404.

In one embodiment, the hypervisor 401 executes a guest operating system410 within a virtual machine 406 created by the hypervisor 401. Inanother embodiment, the guest operating system 410 provides a user ofthe computing device 100 with access to resources within a computingenvironment. In still another embodiment, a resource includes a program,an application, a document, a file, a plurality of applications, aplurality of files, an executable program file, a desktop environment, acomputing environment, or other resource made available to a user of thecomputing device 100. In yet another embodiment, the resource may bedelivered to the computing device 100 via a plurality of access methodsincluding, but not limited to, conventional installation directly on thecomputing device 100, delivery to the computing device 100 via a methodfor application streaming, delivery to the computing device 100 ofoutput data generated by an execution of the resource on a secondcomputing device 100′ and communicated to the computing device 100 via apresentation layer protocol, delivery to the computing device 100 ofoutput data generated by an execution of the resource via a virtualmachine executing on a second computing device 100′, or execution from aremovable storage device connected to the computing device 100, such asa USB device, or via a virtual machine executing on the computing device100 and generating output data. In some embodiments, the computingdevice 100 transmits output data generated by the execution of theresource to another computing device 100′.

In one embodiment, the guest operating system 410, in conjunction withthe virtual machine on which it executes, forms a fully-virtualizedvirtual machine which is not aware that it is a virtual machine; such amachine may be referred to as a “Domain U HVM (Hardware Virtual Machine)virtual machine”. In another embodiment, a fully-virtualized machineincludes software emulating a Basic Input/Output System (BIOS) in orderto execute an operating system within the fully-virtualized machine. Instill another embodiment, a fully-virtualized machine may include adriver that provides functionality by communicating with the hypervisor401. In such an embodiment, the driver may be aware that it executeswithin a virtualized environment. In another embodiment, the guestoperating system 410, in conjunction with the virtual machine on whichit executes, forms a paravirtualized virtual machine, which is awarethat it is a virtual machine; such a machine may be referred to as a“Domain U PV virtual machine”. In another embodiment, a paravirtualizedmachine includes additional drivers that a fully-virtualized machinedoes not include. In still another embodiment, the paravirtualizedmachine includes the network back-end driver and the block back-enddriver included in a control operating system 405, as described above.

Referring now to FIG. 4B, a block diagram depicts one embodiment of aplurality of networked computing devices in a system in which at leastone physical host executes a virtual machine. In brief overview, thesystem includes a management component 404 and a hypervisor 401. Thesystem includes a plurality of computing devices 100, a plurality ofvirtual machines 406, a plurality of hypervisors 401, a plurality ofmanagement components referred to variously as tools stacks 404 ormanagement components 404, and a physical resource 421, 428. Theplurality of physical machines 100 may each be provided as computingdevices 100, described above in connection with FIGS. 1E-1H and 4A.

In greater detail, a physical disk 428 is provided by a computing device100 and stores at least a portion of a virtual disk 442. In someembodiments, a virtual disk 442 is associated with a plurality ofphysical disks 428. In one of these embodiments, one or more computingdevices 100 may exchange data with one or more of the other computingdevices 100 regarding processors and other physical resources availablein a pool of resources, allowing a hypervisor to manage a pool ofresources distributed across a plurality of physical computing devices.In some embodiments, a computing device 100 on which a virtual machine406 executes is referred to as a physical host 100 or as a host machine100.

The hypervisor executes on a processor on the computing device 100. Thehypervisor allocates, to a virtual disk, an amount of access to thephysical disk. In one embodiment, the hypervisor 401 allocates an amountof space on the physical disk. In another embodiment, the hypervisor 401allocates a plurality of pages on the physical disk. In someembodiments, the hypervisor provisions the virtual disk 442 as part of aprocess of initializing and executing a virtual machine 450.

In one embodiment, the management component 404 a is referred to as apool management component 404 a. In another embodiment, a managementoperating system 405 a, which may be referred to as a control operatingsystem 405 a, includes the management component. In some embodiments,the management component is referred to as a tools stack. In one ofthese embodiments, the management component is the tools stack 404described above in connection with FIG. 4A. In other embodiments, themanagement component 404 provides a user interface for receiving, from auser such as an administrator, an identification of a virtual machine406 to provision and/or execute. In still other embodiments, themanagement component 404 provides a user interface for receiving, from auser such as an administrator, the request for migration of a virtualmachine 406 b from one physical machine 100 to another. In furtherembodiments, the management component 404 a identifies a computingdevice 100 b on which to execute a requested virtual machine 406 d andinstructs the hypervisor 401 b on the identified computing device 100 bto execute the identified virtual machine; such a management componentmay be referred to as a pool management component.

Referring now to FIG. 4C, embodiments of a virtual application deliverycontroller or virtual appliance 450 are depicted. In brief overview, anyof the functionality and/or embodiments of the appliance 200 (e.g., anapplication delivery controller) described above in connection withFIGS. 2A and 2B may be deployed in any embodiment of the virtualizedenvironment described above in connection with FIGS. 4A and 4B. Insteadof the functionality of the application delivery controller beingdeployed in the form of an appliance 200, such functionality may bedeployed in a virtualized environment 400 on any computing device 100,such as a client 102, server 106 or appliance 200.

Referring now to FIG. 4C, a diagram of an embodiment of a virtualappliance 450 operating on a hypervisor 401 of a server 106 is depicted.As with the appliance 200 of FIGS. 2A and 2B, the virtual appliance 450may provide functionality for availability, performance, offload andsecurity. For availability, the virtual appliance may perform loadbalancing between layers 4 and 7 of the network and may also performintelligent service health monitoring. For performance increases vianetwork traffic acceleration, the virtual appliance may perform cachingand compression. To offload processing of any servers, the virtualappliance may perform connection multiplexing and pooling and/or SSLprocessing. For security, the virtual appliance may perform any of theapplication firewall functionality and SSL VPN function of appliance200.

Any of the modules of the appliance 200 as described in connection withFIG. 2A may be packaged, combined, designed or constructed in a form ofthe virtualized appliance delivery controller 450 deployable as one ormore software modules or components executable in a virtualizedenvironment 300 or non-virtualized environment on any server, such as anoff the shelf server. For example, the virtual appliance may be providedin the form of an installation package to install on a computing device.With reference to FIG. 2A, any of the cache manager 232, policy engine236, compression 238, encryption engine 234, packet engine 240, GUI 210,CLI 212, shell services 214 and health monitoring programs 216 may bedesigned and constructed as a software component or module to run on anyoperating system of a computing device and/or of a virtualizedenvironment 300. Instead of using the encryption processor 260,processor 262, memory 264 and network stack 267 of the appliance 200,the virtualized appliance 400 may use any of these resources as providedby the virtualized environment 400 or as otherwise available on theserver 106.

Still referring to FIG. 4C, and in brief overview, any one or morevServers 275A-275N may be in operation or executed in a virtualizedenvironment 400 of any type of computing device 100, such as any server106. Any of the modules or functionality of the appliance 200 describedin connection with FIG. 2B may be designed and constructed to operate ineither a virtualized or non-virtualized environment of a server. Any ofthe vServer 275, SSL VPN 280, Intranet UP 282, Switching 284, DNS 286,acceleration 288, App FW 280 and monitoring agent may be packaged,combined, designed or constructed in a form of application deliverycontroller 450 deployable as one or more software modules or componentsexecutable on a device and/or virtualized environment 400.

In some embodiments, a server may execute multiple virtual machines 406a-406 n in the virtualization environment with each virtual machinerunning the same or different embodiments of the virtual applicationdelivery controller 450. In some embodiments, the server may execute oneor more virtual appliances 450 on one or more virtual machines on a coreof a multi-core processing system. In some embodiments, the server mayexecute one or more virtual appliances 450 on one or more virtualmachines on each processor of a multiple processor device.

E. Systems and Methods for Providing A Multi-Core Architecture

In accordance with Moore's Law, the number of transistors that may beplaced on an integrated circuit may double approximately every twoyears. However, CPU speed increases may reach plateaus, for example CPUspeed has been around 3.5-4 GHz range since 2005. In some cases, CPUmanufacturers may not rely on CPU speed increases to gain additionalperformance. Some CPU manufacturers may add additional cores to theirprocessors to provide additional performance. Products, such as those ofsoftware and networking vendors, that rely on CPUs for performance gainsmay improve their performance by leveraging these multi-core CPUs. Thesoftware designed and constructed for a single CPU may be redesignedand/or rewritten to take advantage of a multi-threaded, parallelarchitecture or otherwise a multi-core architecture.

A multi-core architecture of the appliance 200, referred to as nCore ormulti-core technology, allows the appliance in some embodiments to breakthe single core performance barrier and to leverage the power ofmulti-core CPUs. In the previous architecture described in connectionwith FIG. 2A, a single network or packet engine is run. The multiplecores of the nCore technology and architecture allow multiple packetengines to run concurrently and/or in parallel. With a packet enginerunning on each core, the appliance architecture leverages theprocessing capacity of additional cores. In some embodiments, thisprovides up to a 7× increase in performance and scalability.

Illustrated in FIG. 5A are some embodiments of work, task, load ornetwork traffic distribution across one or more processor coresaccording to a type of parallelism or parallel computing scheme, such asfunctional parallelism, data parallelism or flow-based data parallelism.In brief overview, FIG. 5A illustrates embodiments of a multi-coresystem such as an appliance 200′ with n-cores, a total of cores numbers1 through N. In one embodiment, work, load or network traffic can bedistributed among a first core 505A, a second core 505B, a third core505C, a fourth core 505D, a fifth core 505E, a sixth core 505F, aseventh core 505G, and so on such that distribution is across all or twoor more of the n cores 505N (hereinafter referred to collectively ascores 505.) There may be multiple VIPs 275 each running on a respectivecore of the plurality of cores. There may be multiple packet engines 240each running on a respective core of the plurality of cores. Any of theapproaches used may lead to different, varying or similar work load orperformance level 515 across any of the cores. For a functionalparallelism approach, each core may run a different function of thefunctionalities provided by the packet engine, a VIP 275 or appliance200. In a data parallelism approach, data may be paralleled ordistributed across the cores based on the Network Interface Card (NIC)or VIP 275 receiving the data. In another data parallelism approach,processing may be distributed across the cores by distributing dataflows to each core.

In further detail to FIG. 5A, in some embodiments, load, work or networktraffic can be distributed among cores 505 according to functionalparallelism 500. Functional parallelism may be based on each coreperforming one or more respective functions. In some embodiments, afirst core may perform a first function while a second core performs asecond function. In functional parallelism approach, the functions to beperformed by the multi-core system are divided and distributed to eachcore according to functionality. In some embodiments, functionalparallelism may be referred to as task parallelism and may be achievedwhen each processor or core executes a different process or function onthe same or different data. The core or processor may execute the sameor different code. In some cases, different execution threads or codemay communicate with one another as they work. Communication may takeplace to pass data from one thread to the next as part of a workflow.

In some embodiments, distributing work across the cores 505 according tofunctional parallelism 500, can comprise distributing network trafficaccording to a particular function such as network input/outputmanagement (NW I/O) 510A, secure sockets layer (SSL) encryption anddecryption 510B and transmission control protocol (TCP) functions 510C.This may lead to a work, performance or computing load 515 based on avolume or level of functionality being used. In some embodiments,distributing work across the cores 505 according to data parallelism540, can comprise distributing an amount of work 515 based ondistributing data associated with a particular hardware or softwarecomponent. In some embodiments, distributing work across the cores 505according to flow-based data parallelism 520, can comprise distributingdata based on a context or flow such that the amount of work 515A-N oneach core may be similar, substantially equal or relatively evenlydistributed.

In the case of the functional parallelism approach, each core may beconfigured to run one or more functionalities of the plurality offunctionalities provided by the packet engine or VIP of the appliance.For example, core 1 may perform network I/O processing for the appliance200′ while core 2 performs TCP connection management for the appliance.Likewise, core 3 may perform SSL offloading while core 4 may performlayer 7 or application layer processing and traffic management. Each ofthe cores may perform the same function or different functions. Each ofthe cores may perform more than one function. Any of the cores may runany of the functionality or portions thereof identified and/or describedin conjunction with FIGS. 2A and 2B. In this the approach, the workacross the cores may be divided by function in either a coarse-grainedor fine-grained manner. In some cases, as illustrated in FIG. 5A,division by function may lead to different cores running at differentlevels of performance or load 515.

In the case of the functional parallelism approach, each core may beconfigured to run one or more functionalities of the plurality offunctionalities provided by the packet engine of the appliance. Forexample, core 1 may perform network I/O processing for the appliance200′ while core 2 performs TCP connection management for the appliance.Likewise, core 3 may perform SSL offloading while core 4 may performlayer 7 or application layer processing and traffic management. Each ofthe cores may perform the same function or different functions. Each ofthe cores may perform more than one function. Any of the cores may runany of the functionality or portions thereof identified and/or describedin conjunction with FIGS. 2A and 2B. In this the approach, the workacross the cores may be divided by function in either a coarse-grainedor fine-grained manner. In some cases, as illustrated in FIG. 5Adivision by function may lead to different cores running at differentlevels of load or performance.

The functionality or tasks may be distributed in any arrangement andscheme. For example, FIG. 5B illustrates a first core, Core 1 505A,processing applications and processes associated with network I/Ofunctionality 510A. Network traffic associated with network I/O, in someembodiments, can be associated with a particular port number. Thus,outgoing and incoming packets having a port destination associated withNW I/O 510A will be directed towards Core 1 505A which is dedicated tohandling all network traffic associated with the NW I/O port. Similarly,Core 2 505B is dedicated to handling functionality associated with SSLprocessing and Core 4 505D may be dedicated handling all TCP levelprocessing and functionality.

While FIG. 5A illustrates functions such as network I/O, SSL and TCP,other functions can be assigned to cores. These other functions caninclude any one or more of the functions or operations described herein.For example, any of the functions described in conjunction with FIGS. 2Aand 2B may be distributed across the cores on a functionality basis. Insome cases, a first VIP 275A may run on a first core while a second VIP275B with a different configuration may run on a second core. In someembodiments, each core 505 can handle a particular functionality suchthat each core 505 can handle the processing associated with thatparticular function. For example, Core 2 505B may handle SSL offloadingwhile Core 4 505D may handle application layer processing and trafficmanagement.

In other embodiments, work, load or network traffic may be distributedamong cores 505 according to any type and form of data parallelism 540.In some embodiments, data parallelism may be achieved in a multi-coresystem by each core performing the same task or functionally ondifferent pieces of distributed data. In some embodiments, a singleexecution thread or code controls operations on all pieces of data. Inother embodiments, different threads or instructions control theoperation, but may execute the same code. In some embodiments, dataparallelism is achieved from the perspective of a packet engine,vServers (VIPs) 275A-C, network interface cards (NIC) 542D-E and/or anyother networking hardware or software included on or associated with anappliance 200. For example, each core may run the same packet engine orVIP code or configuration but operate on different sets of distributeddata. Each networking hardware or software construct can receivedifferent, varying or substantially the same amount of data, and as aresult may have varying, different or relatively the same amount of load515.

In the case of a data parallelism approach, the work may be divided upand distributed based on VIPs, NICs and/or data flows of the VIPs orNICs. In one of these approaches, the work of the multi-core system maybe divided or distributed among the VIPs by having each VIP work on adistributed set of data. For example, each core may be configured to runone or more VIPs. Network traffic may be distributed to the core foreach VIP handling that traffic. In another of these approaches, the workof the appliance may be divided or distributed among the cores based onwhich NIC receives the network traffic. For example, network traffic ofa first NIC may be distributed to a first core while network traffic ofa second NIC may be distributed to a second core. In some cases, a coremay process data from multiple NICs.

While FIG. 5A illustrates a single vServer associated with a single core505, as is the case for VIP1 275A, VIP2 275B and VIP3 275C. In someembodiments, a single vServer can be associated with one or more cores505. In contrast, one or more vServers can be associated with a singlecore 505. Associating a vServer with a core 505 may include that core505 to process all functions associated with that particular vServer. Insome embodiments, each core executes a VIP having the same code andconfiguration. In other embodiments, each core executes a VIP having thesame code but different configuration. In some embodiments, each coreexecutes a VIP having different code and the same or differentconfiguration.

Like vServers, NICs can also be associated with particular cores 505. Inmany embodiments, NICs can be connected to one or more cores 505 suchthat when a NIC receives or transmits data packets, a particular core505 handles the processing involved with receiving and transmitting thedata packets. In one embodiment, a single NIC can be associated with asingle core 505, as is the case with NIC1 542D and NIC2 542E. In otherembodiments, one or more NICs can be associated with a single core 505.In other embodiments, a single NIC can be associated with one or morecores 505. In these embodiments, load could be distributed amongst theone or more cores 505 such that each core 505 processes a substantiallysimilar amount of load. A core 505 associated with a NIC may process allfunctions and/or data associated with that particular NIC.

While distributing work across cores based on data of VIPs or NICs mayhave a level of independency, in some embodiments, this may lead tounbalanced use of cores as illustrated by the varying loads 515 of FIG.5A.

In some embodiments, load, work or network traffic can be distributedamong cores 505 based on any type and form of data flow. In another ofthese approaches, the work may be divided or distributed among coresbased on data flows. For example, network traffic between a client and aserver traversing the appliance may be distributed to and processed byone core of the plurality of cores. In some cases, the core initiallyestablishing the session or connection may be the core for which networktraffic for that session or connection is distributed. In someembodiments, the data flow is based on any unit or portion of networktraffic, such as a transaction, a request/response communication ortraffic originating from an application on a client. In this manner andin some embodiments, data flows between clients and servers traversingthe appliance 200′ may be distributed in a more balanced manner than theother approaches.

In flow-based data parallelism 520, distribution of data is related toany type of flow of data, such as request/response pairings,transactions, sessions, connections or application communications. Forexample, network traffic between a client and a server traversing theappliance may be distributed to and processed by one core of theplurality of cores. In some cases, the core initially establishing thesession or connection may be the core for which network traffic for thatsession or connection is distributed. The distribution of data flow maybe such that each core 505 carries a substantially equal or relativelyevenly distributed amount of load, data or network traffic.

In some embodiments, the data flow is based on any unit or portion ofnetwork traffic, such as a transaction, a request/response communicationor traffic originating from an application on a client. In this mannerand in some embodiments, data flows between clients and serverstraversing the appliance 200′ may be distributed in a more balancedmanner than the other approached. In one embodiment, data flow can bedistributed based on a transaction or a series of transactions. Thistransaction, in some embodiments, can be between a client and a serverand can be characterized by an IP address or other packet identifier.For example, Core 1 505A can be dedicated to transactions between aparticular client and a particular server, therefore the load 515A onCore 1 505A may be comprised of the network traffic associated with thetransactions between the particular client and server. Allocating thenetwork traffic to Core 1 505A can be accomplished by routing all datapackets originating from either the particular client or server to Core1 505A.

While work or load can be distributed to the cores based in part ontransactions, in other embodiments load or work can be allocated on aper packet basis. In these embodiments, the appliance 200 can interceptdata packets and allocate them to a core 505 having the least amount ofload. For example, the appliance 200 could allocate a first incomingdata packet to Core 1 505A because the load 515A on Core 1 is less thanthe load 515B-N on the rest of the cores 505B-N. Once the first datapacket is allocated to Core 1 505A, the amount of load 515A on Core 1505A is increased proportional to the amount of processing resourcesneeded to process the first data packet. When the appliance 200intercepts a second data packet, the appliance 200 will allocate theload to Core 4 505D because Core 4 505D has the second least amount ofload. Allocating data packets to the core with the least amount of loadcan, in some embodiments, ensure that the load 515A-N distributed toeach core 505 remains substantially equal.

In other embodiments, load can be allocated on a per unit basis where asection of network traffic is allocated to a particular core 505. Theabove-mentioned example illustrates load balancing on a per/packetbasis. In other embodiments, load can be allocated based on a number ofpackets such that every 10, 100 or 1000 packets are allocated to thecore 505 having the least amount of load. The number of packetsallocated to a core 505 can be a number determined by an application,user or administrator and can be any number greater than zero. In stillother embodiments, load can be allocated based on a time metric suchthat packets are distributed to a particular core 505 for apredetermined amount of time. In these embodiments, packets can bedistributed to a particular core 505 for five milliseconds or for anyperiod of time determined by a user, program, system, administrator orotherwise. After the predetermined time period elapses, data packets aretransmitted to a different core 505 for the predetermined period oftime.

Flow-based data parallelism methods for distributing work, load ornetwork traffic among the one or more cores 505 can comprise anycombination of the above-mentioned embodiments. These methods can becarried out by any part of the appliance 200, by an application or setof executable instructions executing on one of the cores 505, such asthe packet engine, or by any application, program or agent executing ona computing device in communication with the appliance 200.

The functional and data parallelism computing schemes illustrated inFIG. 5A can be combined in any manner to generate a hybrid parallelismor distributed processing scheme that encompasses function parallelism500, data parallelism 540, flow-based data parallelism 520 or anyportions thereof. In some cases, the multi-core system may use any typeand form of load balancing schemes to distribute load among the one ormore cores 505. The load balancing scheme may be used in any combinationwith any of the functional and data parallelism schemes or combinationsthereof.

Illustrated in FIG. 5B is an embodiment of a multi-core system 545,which may be any type and form of one or more systems, appliances,devices or components. This system 545, in some embodiments, can beincluded within an appliance 200 having one or more processing cores505A-N. The system 545 can further include one or more packet engines(PE) or packet processing engines (PPE) 548A-N communicating with amemory bus 556. The memory bus may be used to communicate with the oneor more processing cores 505A-N. Also included within the system 545 canbe one or more network interface cards (NIC) 552 and a flow distributor550 which can further communicate with the one or more processing cores505A-N. The flow distributor 550 can comprise a Receive Side Scaler(RSS) or Receive Side Scaling (RSS) module 560.

Further referring to FIG. 5B, and in more detail, in one embodiment thepacket engine(s) 548A-N can comprise any portion of the appliance 200described herein, such as any portion of the appliance described inFIGS. 2A and 2B. The packet engine(s) 548A-N can, in some embodiments,comprise any of the following elements: the packet engine 240, a networkstack 267; a cache manager 232; a policy engine 236; a compressionengine 238; an encryption engine 234; a GUI 210; a CLI 212; shellservices 214; monitoring programs 216; and any other software orhardware element able to receive data packets from one of either thememory bus 556 or the one of more cores 505A-N. In some embodiments, thepacket engine(s) 548A-N can comprise one or more vServers 275A-N, or anyportion thereof. In other embodiments, the packet engine(s) 548A-N canprovide any combination of the following functionalities: SSL VPN 280;Intranet UP 282; switching 284; DNS 286; packet acceleration 288; App FW280; monitoring such as the monitoring provided by a monitoring agent197; functionalities associated with functioning as a TCP stack; loadbalancing; SSL offloading and processing; content switching; policyevaluation; caching; compression; encoding; decompression; decoding;application firewall functionalities; XML processing and acceleration;and SSL VPN connectivity.

The packet engine(s) 548A-N can, in some embodiments, be associated witha particular server, user, client or network. When a packet engine 548becomes associated with a particular entity, that packet engine 548 canprocess data packets associated with that entity. For example, should apacket engine 548 be associated with a first user, that packet engine548 will process and operate on packets generated by the first user, orpackets having a destination address associated with the first user.Similarly, the packet engine 548 may choose not to be associated with aparticular entity such that the packet engine 548 can process andotherwise operate on any data packets not generated by that entity ordestined for that entity.

In some instances, the packet engine(s) 548A-N can be configured tocarry out the any of the functional and/or data parallelism schemesillustrated in FIG. 5A. In these instances, the packet engine(s) 548A-Ncan distribute functions or data among the processing cores 505A-N sothat the distribution is according to the parallelism or distributionscheme. In some embodiments, a single packet engine(s) 548A-N carriesout a load balancing scheme, while in other embodiments one or morepacket engine(s) 548A-N carry out a load balancing scheme. Each core505A-N, in one embodiment, can be associated with a particular packetengine 548 such that load balancing can be carried out by the packetengine. Load balancing may in this embodiment, require that each packetengine 548A-N associated with a core 505 communicate with the otherpacket engines associated with cores so that the packet engines 548A-Ncan collectively determine where to distribute load. One embodiment ofthis process can include an arbiter that receives votes from each packetengine for load. The arbiter can distribute load to each packet engine548A-N based in part on the age of the engine's vote and in some cases apriority value associated with the current amount of load on an engine'sassociated core 505.

Any of the packet engines running on the cores may run in user mode,kernel or any combination thereof. In some embodiments, the packetengine operates as an application or program running is user orapplication space. In these embodiments, the packet engine may use anytype and form of interface to access any functionality provided by thekernel. In some embodiments, the packet engine operates in kernel modeor as part of the kernel. In some embodiments, a first portion of thepacket engine operates in user mode while a second portion of the packetengine operates in kernel mode. In some embodiments, a first packetengine on a first core executes in kernel mode while a second packetengine on a second core executes in user mode. In some embodiments, thepacket engine or any portions thereof operates on or in conjunction withthe NIC or any drivers thereof.

In some embodiments the memory bus 556 can be any type and form ofmemory or computer bus. While a single memory bus 556 is depicted inFIG. 5B, the system 545 can comprise any number of memory buses 556. Inone embodiment, each packet engine 548 can be associated with one ormore individual memory buses 556.

The NIC 552 can in some embodiments be any of the network interfacecards or mechanisms described herein. The NIC 552 can have any number ofports. The NIC can be designed and constructed to connect to any typeand form of network 104. While a single NIC 552 is illustrated, thesystem 545 can comprise any number of NICs 552. In some embodiments,each core 505A-N can be associated with one or more single NICs 552.Thus, each core 505 can be associated with a single NIC 552 dedicated toa particular core 505. The cores 505A-N can comprise any of theprocessors described herein. Further, the cores 505A-N can be configuredaccording to any of the core 505 configurations described herein. Stillfurther, the cores 505A-N can have any of the core 505 functionalitiesdescribed herein. While FIG. 5B illustrates seven cores 505A-G, anynumber of cores 505 can be included within the system 545. Inparticular, the system 545 can comprise “N” cores, where “N” is a wholenumber greater than zero.

A core may have or use memory that is allocated or assigned for use tothat core. The memory may be considered private or local memory of thatcore and only accessible by that core. A core may have or use memorythat is shared or assigned to multiple cores. The memory may beconsidered public or shared memory that is accessible by more than onecore. A core may use any combination of private and public memory. Withseparate address spaces for each core, some level of coordination iseliminated from the case of using the same address space. With aseparate address space, a core can perform work on information and datain the core's own address space without worrying about conflicts withother cores. Each packet engine may have a separate memory pool for TCPand/or SSL connections.

Further referring to FIG. 5B, any of the functionality and/orembodiments of the cores 505 described above in connection with FIG. 5Acan be deployed in any embodiment of the virtualized environmentdescribed above in connection with FIGS. 4A and 4B. Instead of thefunctionality of the cores 505 being deployed in the form of a physicalprocessor 505, such functionality may be deployed in a virtualizedenvironment 400 on any computing device 100, such as a client 102,server 106 or appliance 200. In other embodiments, instead of thefunctionality of the cores 505 being deployed in the form of anappliance or a single device, the functionality may be deployed acrossmultiple devices in any arrangement. For example, one device maycomprise two or more cores and another device may comprise two or morecores. For example, a multi-core system may include a cluster ofcomputing devices, a server farm or network of computing devices. Insome embodiments, instead of the functionality of the cores 505 beingdeployed in the form of cores, the functionality may be deployed on aplurality of processors, such as a plurality of single core processors.

In one embodiment, the cores 505 may be any type and form of processor.In some embodiments, a core can function substantially similar to anyprocessor or central processing unit described herein. In someembodiment, the cores 505 may comprise any portion of any processordescribed herein. While FIG. 5A illustrates seven cores, there can existany “N” number of cores within an appliance 200, where “N” is any wholenumber greater than one. In some embodiments, the cores 505 can beinstalled within a common appliance 200, while in other embodiments thecores 505 can be installed within one or more appliance(s) 200communicatively connected to one another. The cores 505 can in someembodiments comprise graphics processing software, while in otherembodiments the cores 505 provide general processing capabilities. Thecores 505 can be installed physically near each other and/or can becommunicatively connected to each other. The cores may be connected byany type and form of bus or subsystem physically and/or communicativelycoupled to the cores for transferring data between to, from and/orbetween the cores.

While each core 505 can comprise software for communicating with othercores, in some embodiments a core manager (not shown) can facilitatecommunication between each core 505. In some embodiments, the kernel mayprovide core management. The cores may interface or communicate witheach other using a variety of interface mechanisms. In some embodiments,core to core messaging may be used to communicate between cores, such asa first core sending a message or data to a second core via a bus orsubsystem connecting the cores. In some embodiments, cores maycommunicate via any type and form of shared memory interface. In oneembodiment, there may be one or more memory locations shared among allthe cores. In some embodiments, each core may have separate memorylocations shared with each other core. For example, a first core mayhave a first shared memory with a second core and a second share memorywith a third core. In some embodiments, cores may communicate via anytype of programming or API, such as function calls via the kernel. Insome embodiments, the operating system may recognize and supportmultiple core devices and provide interfaces and API for inter-corecommunications.

The flow distributor 550 can be any application, program, library,script, task, service, process or any type and form of executableinstructions executing on any type and form of hardware. In someembodiments, the flow distributor 550 may any design and construction ofcircuitry to perform any of the operations and functions describedherein. In some embodiments, the flow distributor distribute, forwards,routes, controls and/ors manage the distribution of data packets amongthe cores 505 and/or packet engine or VIPs running on the cores. Theflow distributor 550, in some embodiments, can be referred to as aninterface master. In one embodiment, the flow distributor 550 comprisesa set of executable instructions executing on a core or processor of theappliance 200. In another embodiment, the flow distributor 550 comprisesa set of executable instructions executing on a computing machine incommunication with the appliance 200. In some embodiments, the flowdistributor 550 comprises a set of executable instructions executing ona NIC, such as firmware. In still other embodiments, the flowdistributor 550 comprises any combination of software and hardware todistribute data packets among cores or processors. In one embodiment,the flow distributor 550 executes on at least one of the cores 505A-N,while in other embodiments a separate flow distributor 550 assigned toeach core 505A-N executes on an associated core 505A-N. The flowdistributor may use any type and form of statistical or probabilisticalgorithms or decision making to balance the flows across the cores. Thehardware of the appliance, such as a NIC, or the kernel may be designedand constructed to support sequential operations across the NICs and/orcores.

In embodiments where the system 545 comprises one or more flowdistributors 550, each flow distributor 550 can be associated with aprocessor 505 or a packet engine 548. The flow distributors 550 cancomprise an interface mechanism that allows each flow distributor 550 tocommunicate with the other flow distributors 550 executing within thesystem 545. In one instance, the one or more flow distributors 550 candetermine how to balance load by communicating with each other. Thisprocess can operate substantially similarly to the process describedabove for submitting votes to an arbiter which then determines whichflow distributor 550 should receive the load. In other embodiments, afirst flow distributor 550′ can identify the load on an associated coreand determine whether to forward a first data packet to the associatedcore based on any of the following criteria: the load on the associatedcore is above a predetermined threshold; the load on the associated coreis below a predetermined threshold; the load on the associated core isless than the load on the other cores; or any other metric that can beused to determine where to forward data packets based in part on theamount of load on a processor.

The flow distributor 550 can distribute network traffic among the cores505 according to a distribution, computing or load balancing scheme suchas those described herein. In one embodiment, the flow distributor candistribute network traffic according to any one of a functionalparallelism distribution scheme 550, a data parallelism loaddistribution scheme 540, a flow-based data parallelism distributionscheme 520, or any combination of these distribution scheme or any loadbalancing scheme for distributing load among multiple processors. Theflow distributor 550 can therefore act as a load distributor by takingin data packets and distributing them across the processors according toan operative load balancing or distribution scheme. In one embodiment,the flow distributor 550 can comprise one or more operations, functionsor logic to determine how to distribute packers, work or loadaccordingly. In still other embodiments, the flow distributor 550 cancomprise one or more sub operations, functions or logic that canidentify a source address and a destination address associated with adata packet, and distribute packets accordingly.

In some embodiments, the flow distributor 550 can comprise areceive-side scaling (RSS) network driver, module 560 or any type andform of executable instructions which distribute data packets among theone or more cores 505. The RSS module 560 can comprise any combinationof hardware and software, In some embodiments, the RSS module 560 worksin conjunction with the flow distributor 550 to distribute data packetsacross the cores 505A-N or among multiple processors in amulti-processor network. The RSS module 560 can execute within the NIC552 in some embodiments, and in other embodiments can execute on any oneof the cores 505.

In some embodiments, the RSS module 560 uses the MICROSOFTreceive-side-scaling (RSS) scheme. In one embodiment, RSS is a MicrosoftScalable Networking initiative technology that enables receiveprocessing to be balanced across multiple processors in the system whilemaintaining in-order delivery of the data. The RSS may use any type andform of hashing scheme to determine a core or processor for processing anetwork packet.

The RSS module 560 can apply any type and form hash function such as theToeplitz hash function. The hash function may be applied to the hashtype or any the sequence of values. The hash function may be a securehash of any security level or is otherwise cryptographically secure. Thehash function may use a hash key. The size of the key is dependent uponthe hash function. For the Toeplitz hash, the size may be 40 bytes forIPv6 and 16 bytes for IPv4.

The hash function may be designed and constructed based on any one ormore criteria or design goals. In some embodiments, a hash function maybe used that provides an even distribution of hash result for differenthash inputs and different hash types, including TCP/IPv4, TCP/IPv6,IPv4, and IPv6 headers. In some embodiments, a hash function may be usedthat provides a hash result that is evenly distributed when a smallnumber of buckets are present (for example, two or four). In someembodiments, hash function may be used that provides a hash result thatis randomly distributed when a large number of buckets were present (forexample, 64 buckets). In some embodiments, the hash function isdetermined based on a level of computational or resource usage. In someembodiments, the hash function is determined based on ease or difficultyof implementing the hash in hardware. In some embodiments, the hashfunction is determined based on the ease or difficulty of a maliciousremote host to send packets that would all hash to the same bucket.

The RSS may generate hashes from any type and form of input, such as asequence of values. This sequence of values can include any portion ofthe network packet, such as any header, field or payload of networkpacket, or portions thereof. In some embodiments, the input to the hashmay be referred to as a hash type and include any tuples of informationassociated with a network packet or data flow, such as any of thefollowing: a four tuple comprising at least two IP addresses and twoports; a four tuple comprising any four sets of values; a six tuple; atwo tuple; and/or any other sequence of numbers or values. The followingare example of hash types that may be used by RSS:

-   -   4-tuple of source TCP Port, source IP version 4 (IPv4) address,        destination TCP Port, and destination IPv4 address.    -   4-tuple of source TCP Port, source IP version 6 (IPv6) address,        destination TCP Port, and destination IPv6 address.    -   2-tuple of source IPv4 address, and destination IPv4 address.    -   2-tuple of source IPv6 address, and destination IPv6 address.    -   2-tuple of source IPv6 address, and destination IPv6 address,        including support for parsing IPv6 extension headers.

The hash result or any portion thereof may used to identify a core orentity, such as a packet engine or VIP, for distributing a networkpacket. In some embodiments, one or more hash bits or mask are appliedto the hash result. The hash bit or mask may be any number of bits orbytes. A NIC may support any number of bits, such as seven bits. Thenetwork stack may set the actual number of bits to be used duringinitialization. The number will be between 1 and 7, inclusive.

The hash result may be used to identify the core or entity via any typeand form of table, such as a bucket table or indirection table. In someembodiments, the number of hash-result bits are used to index into thetable. The range of the hash mask may effectively define the size of theindirection table. Any portion of the hash result or the hast resultitself may be used to index the indirection table. The values in thetable may identify any of the cores or processor, such as by a core orprocessor identifier. In some embodiments, all of the cores of themulti-core system are identified in the table. In other embodiments, aport of the cores of the multi-core system are identified in the table.The indirection table may comprise any number of buckets for example 2to 128 buckets that may be indexed by a hash mask. Each bucket maycomprise a range of index values that identify a core or processor. Insome embodiments, the flow controller and/or RSS module may rebalancethe network rebalance the network load by changing the indirectiontable.

In some embodiments, the multi-core system 575 does not include a RSSdriver or RSS module 560. In some of these embodiments, a softwaresteering module (not shown) or a software embodiment of the RSS modulewithin the system can operate in conjunction with or as part of the flowdistributor 550 to steer packets to cores 505 within the multi-coresystem 575.

The flow distributor 550, in some embodiments, executes within anymodule or program on the appliance 200, on any one of the cores 505 andon any one of the devices or components included within the multi-coresystem 575. In some embodiments, the flow distributor 550′ can executeon the first core 505A, while in other embodiments the flow distributor550″ can execute on the NIC 552. In still other embodiments, an instanceof the flow distributor 550′ can execute on each core 505 included inthe multi-core system 575. In this embodiment, each instance of the flowdistributor 550′ can communicate with other instances of the flowdistributor 550′ to forward packets back and forth across the cores 505.There exist situations where a response to a request packet may not beprocessed by the same core, i.e. the first core processes the requestwhile the second core processes the response. In these situations, theinstances of the flow distributor 550′ can intercept the packet andforward it to the desired or correct core 505, i.e. a flow distributorinstance 550′ can forward the response to the first core. Multipleinstances of the flow distributor 550′ can execute on any number ofcores 505 and any combination of cores 505.

The flow distributor may operate responsive to any one or more rules orpolicies. The rules may identify a core or packet processing engine toreceive a network packet, data or data flow. The rules may identify anytype and form of tuple information related to a network packet, such asa 4-tuple of source and destination IP address and source anddestination ports. Based on a received packet matching the tuplespecified by the rule, the flow distributor may forward the packet to acore or packet engine. In some embodiments, the packet is forwarded to acore via shared memory and/or core to core messaging.

Although FIG. 5B illustrates the flow distributor 550 as executingwithin the multi-core system 575, in some embodiments the flowdistributor 550 can execute on a computing device or appliance remotelylocated from the multi-core system 575. In such an embodiment, the flowdistributor 550 can communicate with the multi-core system 575 to takein data packets and distribute the packets across the one or more cores505. The flow distributor 550 can, in one embodiment, receive datapackets destined for the appliance 200, apply a distribution scheme tothe received data packets and distribute the data packets to the one ormore cores 505 of the multi-core system 575. In one embodiment, the flowdistributor 550 can be included in a router or other appliance such thatthe router can target particular cores 505 by altering meta dataassociated with each packet so that each packet is targeted towards asub-node of the multi-core system 575. In such an embodiment, CISCO'svn-tag mechanism can be used to alter or tag each packet with theappropriate meta data.

Illustrated in FIG. 5C is an embodiment of a multi-core system 575comprising one or more processing cores 505A-N. In brief overview, oneof the cores 505 can be designated as a control core 505A and can beused as a control plane 570 for the other cores 505. The other cores maybe secondary cores which operate in a data plane while the control coreprovides the control plane. The cores 505A-N may share a global cache580. While the control core provides a control plane, the other cores inthe multi-core system form or provide a data plane. These cores performdata processing functionality on network traffic while the controlprovides initialization, configuration and control of the multi-coresystem.

Further referring to FIG. 5C, and in more detail, the cores 505A-N aswell as the control core 505A can be any processor described herein.Furthermore, the cores 505A-N and the control core 505A can be anyprocessor able to function within the system 575 described in FIG. 5C.Still further, the cores 505A-N and the control core 505A can be anycore or group of cores described herein. The control core may be adifferent type of core or processor than the other cores. In someembodiments, the control may operate a different packet engine or have apacket engine configured differently than the packet engines of theother cores.

Any portion of the memory of each of the cores may be allocated to orused for a global cache that is shared by the cores. In brief overview,a predetermined percentage or predetermined amount of each of the memoryof each core may be used for the global cache. For example, 50% of eachmemory of each code may be dedicated or allocated to the shared globalcache. That is, in the illustrated embodiment, 2 GB of each coreexcluding the control plane core or core 1 may be used to form a 28 GBshared global cache. The configuration of the control plane such as viathe configuration services may determine the amount of memory used forthe shared global cache. In some embodiments, each core may provide adifferent amount of memory for use by the global cache. In otherembodiments, any one core may not provide any memory or use the globalcache. In some embodiments, any of the cores may also have a local cachein memory not allocated to the global shared memory. Each of the coresmay store any portion of network traffic to the global shared cache.Each of the cores may check the cache for any content to use in arequest or response. Any of the cores may obtain content from the globalshared cache to use in a data flow, request or response.

The global cache 580 can be any type and form of memory or storageelement, such as any memory or storage element described herein. In someembodiments, the cores 505 may have access to a predetermined amount ofmemory (i.e. 32 GB or any other memory amount commensurate with thesystem 575). The global cache 580 can be allocated from thatpredetermined amount of memory while the rest of the available memorycan be allocated among the cores 505. In other embodiments, each core505 can have a predetermined amount of memory. The global cache 580 cancomprise an amount of the memory allocated to each core 505. This memoryamount can be measured in bytes, or can be measured as a percentage ofthe memory allocated to each core 505. Thus, the global cache 580 cancomprise 1 GB of memory from the memory associated with each core 505,or can comprise 20 percent or one-half of the memory associated witheach core 505. In some embodiments, only a portion of the cores 505provide memory to the global cache 580, while in other embodiments theglobal cache 580 can comprise memory not allocated to the cores 505.

Each core 505 can use the global cache 580 to store network traffic orcache data. In some embodiments, the packet engines of the core use theglobal cache to cache and use data stored by the plurality of packetengines. For example, the cache manager of FIG. 2A and cachefunctionality of FIG. 2B may use the global cache to share data foracceleration. For example, each of the packet engines may storeresponses, such as HTML data, to the global cache. Any of the cachemanagers operating on a core may access the global cache to servercaches responses to client requests.

In some embodiments, the cores 505 can use the global cache 580 to storea port allocation table which can be used to determine data flow basedin part on ports. In other embodiments, the cores 505 can use the globalcache 580 to store an address lookup table or any other table or listthat can be used by the flow distributor to determine where to directincoming and outgoing data packets. The cores 505 can, in someembodiments read from and write to cache 580, while in other embodimentsthe cores 505 can only read from or write to cache 580. The cores mayuse the global cache to perform core to core communications.

The global cache 580 may be sectioned into individual memory sectionswhere each section can be dedicated to a particular core 505. In oneembodiment, the control core 505A can receive a greater amount ofavailable cache, while the other cores 505 can receiving varying amountsor access to the global cache 580.

In some embodiments, the system 575 can comprise a control core 505A.While FIG. 5C illustrates core 1 505A as the control core, the controlcore can be any core within the appliance 200 or multi-core system.Further, while only a single control core is depicted, the system 575can comprise one or more control cores each having a level of controlover the system. In some embodiments, one or more control cores can eachcontrol a particular aspect of the system 575. For example, one core cancontrol deciding which distribution scheme to use, while another corecan determine the size of the global cache 580.

The control plane of the multi-core system may be the designation andconfiguration of a core as the dedicated management core or as a mastercore. This control plane core may provide control, management andcoordination of operation and functionality the plurality of cores inthe multi-core system. This control plane core may provide control,management and coordination of allocation and use of memory of thesystem among the plurality of cores in the multi-core system, includinginitialization and configuration of the same. In some embodiments, thecontrol plane includes the flow distributor for controlling theassignment of data flows to cores and the distribution of networkpackets to cores based on data flows. In some embodiments, the controlplane core runs a packet engine and in other embodiments, the controlplane core is dedicated to management and control of the other cores ofthe system.

The control core 505A can exercise a level of control over the othercores 505 such as determining how much memory should be allocated toeach core 505 or determining which core 505 should be assigned to handlea particular function or hardware/software entity. The control core505A, in some embodiments, can exercise control over those cores 505within the control plan 570. Thus, there can exist processors outside ofthe control plane 570 which are not controlled by the control core 505A.Determining the boundaries of the control plane 570 can includemaintaining, by the control core 505A or agent executing within thesystem 575, a list of those cores 505 controlled by the control core505A. The control core 505A can control any of the following:initialization of a core; determining when a core is unavailable;re-distributing load to other cores 505 when one core fails; determiningwhich distribution scheme to implement; determining which core shouldreceive network traffic; determining how much cache should be allocatedto each core; determining whether to assign a particular function orelement to a particular core; determining whether to permit cores tocommunicate with one another; determining the size of the global cache580; and any other determination of a function, configuration oroperation of the cores within the system 575.

F. Systems and Methods for an HP Addressing Environment

Referring now to FIG. 6, an embodiment of an environment for providingIntranet Internet Protocol (IIP) addresses to users and/or clients isdepicted. The IIP addressing environment provided by the appliance 200and/or client 102 may be used for: 1) assigning, based on policy,temporal and/or status information, an IIP address 282 to a user from aplurality of IIP addresses designated to the user for accessing anetwork via the appliance, 2) providing an IIP address 282 assigned tothe user to an application on a client requesting resolution of theinternet protocol address of the client 102, and 3) providing amechanism to determine the IIP address 282 assigned to the user via aconfigurable user domain name associated with the user's IIP address282.

In brief overview, the appliance 200 provides an IIP pool 610 of IIPaddresses 282A-282N to be assigned and/or used by one or more users. TheIIP pool 610 may include a pool 612 of free or unassigned IIP addresses,i.e. a free pool 613, a pool 614 of IIP addresses that may be reclaimed,i.e., a reclaim pool 614, and/or a pool 616 of IIP addresses that may beassigned via transfer, i.e., a transfer pool 616, such as via thetransfer of a session 645, e.g., a SSL VPN session provided by theappliance 200. In some embodiments, if an IIP address 282 is notavailable from the IIP pool 610, then a mapped IP (MIP) 640 may be usedto provide a client or a user an IIP address 282. For mapped IP, theappliance 200 intercepts an incoming client's IP and replaces it with aMIP address. Any servers sitting behind the appliance 200 see a MIPinstead of a the client's actual IP address in the IP header field oftraffic directed to them.

A set of one or more IIP addresses 282A-282N may be designated for orassociated with a user. In one embodiment, the appliance 200 via an IIPpolicy 620 provides a user with an IIP address from a plurality of IIPaddresses 282A-282N designated for the user. For example, the IIP policy620 may indicate to provide the user with the most recently used IIPaddress 282 of the user. The appliance 200 includes a database or table650 for maintaining an association of IIP addresses 286 to entities,such as users.

In additional overview, the appliance 200 provides a mechanism forquerying the IIP address 282 assigned to and/or used by the user. Theappliance 200 may be configured with a user domain name policy 630specifying a domain suffix 635 to associate with an identifier of theuser. For example, the domain name policy 630 may indicate to append thedomain suffix “mycompany.com” 635 to a user identifier, such as the userid of the user when logged into the appliance 200 or network 104′. As aresult, in some embodiments, the appliance 200 associates the userdomain name 637 of <user id>.<domain suffix>, e.g.,“userA.mycompany.com” with the IIP address assigned to the user. Theappliance 200 may store in the domain name service (DNS) 286, or DNScache the user domain name 637 in association with the IIP address 282The appliance 200 can resolve any DNS queries or ping commands based onthe user domain name 637 by providing the associated IIP address 232.

In further overview, the client agent 120 provides a mechanism by whichthe IIP address 282 is provided to an application. The client agent 120includes an interception or hooking mechanism 350 for intercepting anyapplication programming interface (API) calls of the application relatedto determining or resolving the internet protocol address of the client102, such as for example, gethostbyname. Instead of providing theinternet protocol address of the client 102 identified in the networkstack 310, e.g., the IP address of the client on network 104, the clientagent 120 provides the IIP address 282 assigned to the user via theappliance 200, such as the IIP address 282 of the client 102 or user ofthe client 102 on the second network 104′ connected from the client 102on a first network 104 via a SSL VPN connection of the appliance.

In more detail, the appliance 200 provides an IIP address 282 to a useror the client of the user. In one embodiment, the IIP address 282 is theinternet protocol address of the user, or the client used by the user,for communications on the network 104′ accessed via the appliance 200.For example, the user may communicate on a first network 104 via anetwork stack 310 of a client 102 that provides an internet protocol(IP) address for the first network 104, such as for example,200.100.10.1. From client 102 on the first network 104, the user mayestablish a connection, such as an SSL VPN connection, with a secondnetwork 104′ via the appliance 200. The appliance 200 provides an IIPaddress 282 for the second network 104′ to the client and/or user, suchas 192.10.1.1. Although the client 102 has an IP address on the firstnetwork 104 (e.g., 200.100.10.1), the user and/or client has an IIPaddress 282 or second network IP address (e.g., 192.10.1.1) forcommunications on the second network 104′. In one embodiment, the IIPaddress 282 is the internet protocol address assigned to the client 102on the VPN, or SSL VPN, connected network 104′. In another embodiment,the appliance 200 provides or acts as a DNS 286 for clients 102communicating via the appliance 200. In some embodiments, the appliance200 assigns or leases internet protocol addresses, referred to as IIPaddresses 282, to client's requesting an internet protocol address, suchas dynamically via Dynamic Host Configuration Protocol (DHCP).

The appliance 200 may provide the IIP address 282 from an IIP pool 610of one or more IIP addresses 282A-282N. In some embodiments, theappliance 200 obtains a pool of internet protocol addresses on network104′ from a server 106 to use for the IIP pool 610. In one embodiment,the appliance 200 obtains an IIP address pool 610, or portion thereof,from a DNS server 606, such as one provided via server 106. In anotherembodiment, the appliance 200 obtains an IIP address pool 610, orportion thereof, from a Remote Authentication Dial In User Service,RADIUS, server 608, such as one provided via server 106. In yet anotherembodiment, the appliance 200 acts as a DNS server 286 or provides DNSfunctionally 286 for network 104′. For example, a vServer 275 may beconfigured as a DNS 286. In these embodiments, the appliance 200 obtainsor provides an IIP pool from the appliance provided DNS 286.

The appliance 200 may designate, assign or allocate IIP addresses forany of the following entities: 1) user, 2) group, 3) vServer, and d)global. In some embodiments, the IIP pool 610 may be designated or usedfor assigning IIP addresses 286 to users. In other embodiments, IIP pool610 may include IIP addresses 286 to be assigned to or used by servicesof the appliance 200, such as vServers 275. In other embodiments, IIPpool 610 may include IIP addresses 286 to be assigned to or used byglobal or group entities of the appliance 200. In one embodiment, theIIP pool 610 may comprise a single pool of IIP addresses. In anotherembodiment, the IIP pool 610 may comprise multiple pools or sub-pools ofIIP addresses. In some embodiments, the IIP pool 610 comprises a freeIIP pool 612. In other embodiments, the IIP pool 610 comprises areclaimed IIP pool 614. In yet another embodiment, the IIP pool 610comprises a transfer IIP pool 616. In some embodiments, the IIP pool 610comprises any combination of a free IIP pool 612, a reclaimed IIP pool614 and/or a transfer IIP pool 616. In one embodiment, the free IIP pool413 comprises IP addresses which are available for usage. In someembodiments, the reclaimed IIP pool 614 comprises IP addresses which areassociated with an entity, such as a user, group or vServer, but areinactive and available for usage. In other embodiments, the transfer IIPpool 616 comprises IP addresses that are active but can be madeavailable through a transfer login or transfer session process.

In some embodiments, the appliance 200 may list or enumerate internetprotocol addresses used for IIP addresses in the IIP pool 610, or insome embodiments, any of the sub-pools 612, 614, 616, in an order orpriority. In some embodiments, the appliance 200 enumerates or lists theIIP addresses of a pool according to the following scheme: 1) user, 2)group, 3) vServer, and d) global. In one embodiment, the appliance 200provides an IIP address from an IIP pool 610 for assignment based on theorder or priority. For example, the appliance 200 may try to obtain afree IIP address from the user associated IP free pool 612 first. If anIIP address is not available from the user portion of the pool, theappliance 200 may then try to obtain a free IIP address from the groupportion of the pool 612, and so on, via the vServer and global portionsof the pool until an IIP address can be assigned. Likewise, theappliance 200 may prioritize the sub-pools 612, 614, and 616, in anyorder or combination, to search for IIP addresses to assign. Forexample, the appliance 200 may first search the free IIP pool 612, thenthe reclaimed IIP pool 616 and then the transfer IIP pool 616 for IIPaddresses.

The appliance 200 may comprise any type and form of database or table650 for associating, tracking, managing or maintaining the designation,allocation and/or assignment of IIP addresses to a 1) user, 2) group, 3)vServer, and/or d) global entities from the IIP pool 610. In oneembodiment, the appliance 200 implements an Internet Protocol LightWeight Database Table (IPLWDB) 650. In some embodiments, the IPLWDB 650maintains entries which provide a one-to-one mapping of an IP addresswith or to an entity. In another embodiment, once an entity uses or isassigned an IIP address 282, the IPLWDB maintains the associationbetween the entity and IIP address, which may be referred to as “IIPstickiness” or having the IIP address “stuck” to an entity. In oneembodiment, IIP stickiness refers to the ability or effectiveness of theappliance 200 to maintain or hold the association between the entity andthe IIP address. In some embodiments, IIP stickiness refers to theability or effectiveness of the appliance 200 to maintain the entity/IIPaddress relationship or assignment via any changes in the system, suchas a user logging in and out of the appliance, or changing accesspoints. In some embodiments, the IPLWDB 650 comprises a hash table,which is hashed based on any one or more of the 1) user, 2) group, 3)vServer, and/or d) global entities. The IPLWDB 650 may comprise a hashof the user and any other information associated with the user, such asclient 102, or network 104 of client 104.

The IPLWDB 650 may track, manage or maintain any status and temporalinformation related to the IIP address/entity relationship. In oneembodiment, the IPLWDB 650 maintains if the IIP address for the entityis currently active or inactive. For example, in some embodiments, theIPLWDB 650 identifies an IIP address 282 as active if it is currentlyused in an SSL VPN session via the appliance 200. In another embodiment,the IPLWDB 650 maintains temporal data for the IIP address use by theentity: such as when first used, when last used, how long has been used,and when most recently used. In other embodiments, the IPLWDB 650maintains information on the type or source of usage, such as, in thecase of user, what client 102 or network 104 used from, or for whattransactions or activities were performed using the assigned IIPaddress.

In some embodiments, the IPLWDB 650 tracks, manages and maintainsmultiple IIP addresses used by an entity. The IPLWDB 650 may use one ormore IIP policies 620 for determining which IIP address of a pluralityof IIP addresses to assign or provide to an entity, such as a user. Inone embodiment, the IIP policy 620 may specify to provide for assignmentthe most recently or last used IIP address of the user. In someembodiments, the IIP policy 620 may specify to provide for assignmentthe most used IIP address of the user. In other embodiments, the IIPpolicy 620 may specify to provide the least used IIP address of theuser. In another embodiment, the IIP policy 620 may specify the order orpriority for which to provide IP addresses of the user, for example,from the most recent to least recent. In yet another embodiment, the IIPpolicy 620 may specify which IIP pool 610 or sub-pool 612, 614, 616 touse, and/or in which order. In some embodiments, the IIP policy 620 mayspecify whether or not to use a mapped IP address, and under whatconditions, such as when an inactive IIP address of the user is notavailable. In other embodiments, the IIP policy 620 may specify whetheror not to transfer a session or login of the user, and under whatconditions.

In some embodiments, the appliance 200 can be configured to bind or makethe association of one or more IIP addresses 282 to an entity, such as auser. For example, in some embodiments, the associations in IPLWDB 650are updated or maintained via bind and unbind commands via the appliance200. In one embodiment, the following command can be issued to theappliance 200 via a command line interface (CLI) 212 or GUI 210:

-   -   bind aaa user <user-name> [-intranetip <ip_addr>] [<netmask>]        For example, if an administrator of the appliance 200 intends to        associate the IIP addresses 282 of 10.102,4,189, 10.102.4.1 and        10.102.4.2 with a user “nsroot”, then the administrator may        issue the following commands:

bind aaa user nsroot -intranetip 10.102.4.189 255.255.255.255

bind aaa user nsroot -intranetip 10.102.4.0 255 255.255.255.252

In one embodiment, the netmask value provides a mechanism for assigninga range of IIP addresses to a user. In some embodiments, the netmaskvalue is optional and the default is 255.255.255.255. For example, thefollowing commands are equivalent:

bind aaa user nsroot -intranetip 10.102.4.189

bind aaa user nsroot -intranetip 10.102.4.189 255.255.255.255

Likewise, the administrator 200 or other user may disassociate an IIPaddress with an entity, such as a user, via an unbind command. In someembodiments, the unbind command may have similar format as the bindcommand. In one embodiment, if the IIP address is active, the bind orunbind command will not be processed. In other embodiments, if the IIPaddress is active, the appliance transmits a reset (RST) command to allthe client and server connections associated with the active session,and then proceeds to make any changes associated with the issued bind orunbind command. In another embodiment, the appliance 200 updates theassociated client and server connections with any updated IIP addressinformation. In one embodiment, the appliance 200 re-establishes theassociated client and server connections with the changed IIP address.

In some embodiments, the appliance 200 provides a mechanism and/ortechnique for determining the IIP address 282 of a user. In oneembodiment, the appliance 200 is configured via a user domain namepolicy 630, which provides information on specifying a user domain 637.In one embodiment, the user domain policy 630 specifies a domain suffix635 to be used in forming the user domain 637. For example, the userdomain policy 630, in some embodiments, may be specified by thefollowing command:

-   -   add vpn sessionaction <name> [-httpPort <port> . . . ] [-winsIP        <ip_addr>] . . . [-homepage <URL>] [-iipdnssuffix <string>]        In one embodiment, the iipdnssuffix 635 specifies a string, such        as a domain name, that will be appended to the user id/name to        form a user domain name 637. The user id may be the login name        of the user, an alias or nickname of the user, or any user        identification associated with the user's profile. In one        embodiment, the domain suffix 635 identifies the domain name of        the network 104 or network 104′. In other embodiments, the        domain suffix 635 may comprise a domain name or host name of the        appliance 200. In yet other embodiments, the domain suffix 635        may be any desired, predetermined or custom string for        identifying the user domain name 637.

In the case of a user having multiple IIP addresses 282 activeconcurrently, the user domain name policy 630 may specify an instanceidentifier or any other character or symbol to differentiate between afirst instance and a second instance of a VPN session of the user. Forexample, the policy 630 may specify to include a number after the userid, such as <userid><Instance Number> or <userid>_<#>. In otherembodiments, the policy 630 specifies to only associate or provide asingle user domain name 637 for a user. For example, in one embodiment,the user domain name 637 is associated with the first session. In otherembodiments, the user domain name 637 is associated with the most recentsession.

Although the user domain policy 630 is described as providing a domainsuffix 635 to a user identifier to form the user domain name 637, theuser domain policy 630 may specify any portion of the user domain name637. For the example, the user domain policy 630 may specify the formatfor the user identifier or which type of user id to use, such as anidentified portion of the user's profile. In some embodiments, bydefault, the domain suffix 635 may be the same domain name as thenetwork 104. In another embodiment, the user domain policy 630 mayspecify a format for or additions or modifications to the domain name ofthe network 104 in providing the user domain name 637.

When a user logs in and gets assigned an IIP address 282, the appliance200 stores a record associating the user id/name, or user domain name637, and IIP address 282. In some embodiments, the appliance 200 storesthe record in DNS 286, or a DNS cache, on the appliance 200. In anotherembodiment, the appliance 200 stores the record in a DNS 606 on server106. In other embodiments, the appliance 200 stores the record in theIPLWDB 650. The appliance 200 can query a DNS with the user domain name637 and obtain the assigned IIP address 286. A user logged into theappliance 200 via SSL VPN get the IIP address of another user by usingDNS instead of having to remember the IP address. For example, a user onclient 102 can ping the IIP address of another user. The client agent120 can intercept such requests and query the DNS 286 of the appliance200 to determine the IIP address 282 assigned the user domain name. Insome embodiments, without logging into the appliance 200 via SSLVPN, aclient can query the IIP address 282 of a user by sending a DNS queryrequest to the DNS 286 of the appliance 200.

In some embodiments, the client agent 120 provide an interception orhooking mechanism 350 for intercepting any requests for the local IPaddress of the client 102, and returning or replying with an IIP address282, such as the IIP address 282 assigned to the user. In someembodiments, the hooking mechanism 350 may include any of the mechanismsof the interceptor 350 described above in conjunction with FIG. 3. Inother embodiments, the hooking mechanism 350 may include any type andform of hooking mechanism 350, such as application level hook procedureor function. In one embodiment and by way of example, the hookingmechanism 350 comprises any of the Windows API calls for setting aapplication hooking procedure, such as via the SetWindowsHookEx APIcall. In some embodiments, the SetWindowsHookEx function installs anapplication-defined hook procedure into a hook chain.

Depending on the operating system of the client 102, the client agent120 may use the corresponding APIs of the OS to install, add, modify oruse a hook procedure 350 to hook or intercept messages of anapplication. A hook procedure 350 may be installed to monitor the systemfor certain types of events, which are associated either with a specificthread or with all threads in the same space as the calling thread. Inone embodiment, a hook, such as hooking mechanism 350, is a point in thesystem message-handling mechanism where an application, such as theclient agent 120, can install a subroutine to monitor the messagetraffic in the system and process certain types of messages before themessages reach the target processing function. In some embodiments, thehooking mechanism 350 may intercept or hook any of the followingfunction calls or messages of an application: gethostbyname,getaddrinfo, and getsockname. In other embodiments, the hookingmechanism 350 may hook any of the Windows Socket API extensions such asWSAIoctl, WSALookupServiceBegin, WSALookupServiceNext, andWSALookupServiceEnd.

In one embodiment, the client agent 120 transmits a request to theappliance 200 to determine the IIP address 282 of the host nameintercepted by the hooking mechanism 350. In some embodiments, theappliance 200 looks up the corresponding IIP address 282 of the hostname of the client 102 in a DNS, such as DNS 286 on appliance 200 or DNS606 on a server. In other embodiments, the client agent 120 uses theuser domain name 637 of the user associated with the application to pingor DNS query the IIP address 282. In some embodiments, the client agent120 transmits the local IP address of the client 102 and the appliance200 queries the corresponding IIP address 282. In one embodiment, theappliance 200 stores the name of the client 102 in association with theuser and/or IIP address in the IPLWDB 650. In other embodiments, theclient agent 120 has cached the IIP address of the user or client 102,and thus, does not need to query the appliance 200. For example, uponestablishment of a SSL VPN connection, the appliance 200 may transmitthe IIP address 282 to the client 102. With the hooking mechanism 350,instead of providing the client's local IP address (the client's addresson the first network 104), the client agent 120 provides the IIP address282 of the client (the client's or user's address on the second network104′).

In some embodiments, the hooking mechanism 350 of the client agent 120is used to return the IIP address for supporting the transparent andseamless use of online collaboration tools via SSL VPN connections. Inone embodiment, the application is a NetMeeting application manufacturedby the Microsoft Corporation of Redmond, Wash. In some embodiments, anyof the applications 230 may comprise any type of hosted service orproducts, such as GoToMeeting™ provided by Citrix Online Division, Inc.of Santa Barbara, Calif., WebEx™ provided by WebEx, Inc. of Santa Clara,Calif., or Microsoft Office LiveMeeting provided by MicrosoftCorporation of Redmond, Wash. With the hooking mechanism 350 providingthe IIP address 282 assigned to the client via the SSL VPN connection,the application does not need to be modified to work as designed via theSSL VPN session. The hooking mechanism 350 provides the IIP address 282of the client 102 or user if the client 102 instead of the local IPaddress when making a request to get the IP address of the client 102.

C. IIP Address “Stickiness” to a User

Referring now to FIG. 7, an embodiment of steps of a method 700 forassigning an IIP address 282 to a user is depicted. In one embodiment,the method 700 is practiced to provide IIP address stickiness for auser. In some embodiments, an SSL VPN user may login and logout of theappliance 200 multiple times from different computers. For example, theuser may roam from computing device to computing device or switch fromone location to another. In some example, an SSL VPN user may be on amobile device and have the network connectivity disrupted causing thedevice to re-establish the SSL VPN connection. With the techniquesdepicted by method 700, the SSL VPN user may get assigned the same IIPaddress 282 for each of those sessions. In some embodiments, theappliance 200 may be configured with policies 620 specifying what IIPaddress 282 should be assigned to a user.

In brief overview of method 500, at step 505, the appliance 200designates a plurality of IIP address 282A-292N to a user, such as anSSL VPN user, from a pool 610 of IIP addresses. At step 710, theappliance 200 receives a request from a client 102 operated by the userto establish a connection via the appliance 200 to a network 104′, suchas an SSL VPN connection. At step 715, the appliance 200 assigns to theclient or the user an IIP address 282 on network 104′ from the IIPaddress pool 610. The appliance 200 may make the assignment based onpolicy 620, temporal information or the status of any of the designatedIIP addresses 282A-282N for the user. For example, in one embodiment,the appliance 200 assigns the most recently used IIP address 282 of theuser to the client 102. At step 725, in some embodiments, the appliance200 determines whether to provide a mapped IP or to transfer a session.For example, if an inactive IIP address 282 is not available forassigning to the user, the appliance 200 may opt to use a MIP address atstep 730 or to request the user to transfer an active session to thecurrent request at step 735.

In further detail, at step 705, the appliance 200 may designate orallocate any set of one or more IIP addresses 282A-282N for a user. Insome embodiments, the appliance 200 designates one IIP address 282. Inother embodiments, the appliance 200 designates up to a predeterminednumber of multiple IIP addresses 282A-282N for the user, such as 2, 3,4, 5, 6, 7, 9, 10, 15, 20 or 26 IIP addresses. In one embodiment, themultiple IIP addresses 282A-228N comprise a continuous range of IPaddresses on network 104′, for example, IP addresses 200.10.1.1 to200.20.1.10. In another embodiment, the multiple IIP addresses 282A-282Ncomprises any set of IP addresses on network 104′ that are notsubsequent to each other. In yet another embodiment, the multiple IIPaddresses 282A-282N are any combination of subsequent IP address rangesand single or separate IP addresses.

In one embodiment, the appliance 200 obtains a set of internet protocoladdresses from a DNS for the network 104′ accessed via the appliance200. For example, the appliance 200 may obtain a set of IP addresses forthe intranet from a DNS server 606 or a RADIUS server 708. In anotherexample, the appliance 200 may provide or act as a DNS 286 and allocatethe IP addresses for the intranet. In some embodiments, one or more IIPaddresses 282A-282N may be associated or designated with a user via abind or similar command issued at the CLI 212 or GUI 210 of theappliance 200. In other embodiments, the appliance 200 may obtain from aDNS IP addresses 282A-282N on network 104's that are associated with auser. In some embodiments, the appliance 200 designates a portion of thefree IIP pool 612 to the user. In other embodiments, the appliance 200may designate or reclaim a portion of the reclaim IIP pool 614 to theuser.

At step 710, the user via client 102 transmits a request to theappliance 200 to establish a connection to the network 104′. In someembodiments, the appliance 200 identifies the user from the request. Inother embodiments, the appliance 200 identifies the user from receipt oflogin or authentication credentials. For example, in some embodiments,the user submits a user id and password via a URL or web-page of theappliance 200. In one embodiment, the client agent 120 requests toestablish a tunnel connection with the appliance 200 using any type andform of tunneling protocol. In another embodiment, the client agent 120requests to establish a virtual private network connection via theappliance 200 to a network 104. For example, the client agent 120 mayestablish a virtual private network connection with the appliance 200 toconnect the client 102 on the first network 104 to a second network104′. In some embodiments, the client agent 120 establishes a SSL VPNconnection with the appliance 200. In yet another embodiment, the clientagent 120 establishes a tunnel or virtual private network connectionusing Transport Layer Secure (TLS) protocol. In one embodiment, theclient agent 120 requests to establish a tunnel connection using theCommon Gateway Protocol (CGP) manufactured by Citrix Systems, Inc. ofFt. Lauderdale, Fla.

At step 715, the appliance 200, in response to receiving the requestfrom the user or the client 102, assigns an IIP address 282 on thesecond network 104′ from the designated set of IIP addresses 282A-282Nof the user. In one embodiment, the appliance 200 determines the IIPaddress 282 to assign based on an IIP policy 620. For example, in someembodiments to maintain IIP stickiness, the appliance 200 via IIP policy620 determines the most recently used IIP address 282 of the user. Inother embodiments to maintain IIP stickiness, the appliance 200 viainformation tracked by the IPLWDB 650 determines the most used IIPaddress 282 of the user from the set of IIP addresses 282A-282N. In someembodiments, in the case of one or more active SSL VPN sessions, theappliance 200 determines the next most recently used or most used IIPaddress 282 of the user. In yet other embodiments, the appliance 200determines an appropriate, desired or policy-driven IIP address 282 toassign the user from the designated set of user IIP addresses 282A-282Nby any combination of policy 635, status of sessions associated with theuser's IIP addresses 282A-282N, and temporal information of sessionsassociated with the user's IIP addresses 282A-282N.

In one embodiment, the appliance 200 may use any sub-pool 612, 614 or616 of the IP pool 610 to assign an IIP address 282 to the user. In someembodiment, the free IIP pool 612 may not have an available IIP addressof the user. For example, all the IIP addresses of the user are markedas active or already assigned to a session. As such, in theseembodiments, the appliance 200 may search the reclaim IIP pool 614 forany IIP addresses of the user assigned but available to reclaim. Instill another embodiment, the appliance 200 may search the transfer IIPpool 616 for any IIP addresses of the user. In yet other embodiments,the appliance 200 may search any designated allocations or pools forgroup, global or vServer IIP addresses for an IP address that may bedesignated and assigned for the user or otherwise provided as a mappedIP address. In some embodiments, the appliance 200 searches portions ofthe IP pool 610 for IIP addresses of the user in an ordered orprioritized manner, such as the free IIP pool 612, first, the reclaimIIP pool 614, second and the transfer IIP pool 616 third. In oneembodiment, the search order or priority may be specified by a policy620.

In many embodiments, the appliance 200 provides a previously assignedIIP address 282 of the user from the free IIP pool 612 or the reclaimIIP pool 614. In some embodiments, the appliance 200 provides the userwith the most recently or last assigned IIP address to provide IIPstickiness. However, at step 725, in some embodiments, the appliance 200determines whether to provide a mapped IP 640 or a transfer session 645.In some embodiments, an IIP policy 620 specifies whether to use a mappedIP 640 or a transfer session 645 in cases of the appliance 200 notfinding an available IIP address 282 of the user from the free IIP pool612 and/or the reclaimed IIP pool 614. In other embodiments, an IIPpolicy 620 may specify to use a Mapped IP 640 in cases of the appliance200 not finding an inactive IIP address in any pool 610, or an availableIIP address in the free IIP pool 612. In one embodiment, if the IIPpolicy 620 specifies to use a Mapped IP 640 at step 725, then, at step730 provides a Mapped IP 640 instead of using an assigned IIP address272.

In the cases of using a Mapped IP 640, the appliance 200 modifies anypackets to and from the client 102 with an IIP address 282 of thenetwork 104′. For example, instead of assigning the user a userdesignated IIP address 282, the appliance 200 may use any available IIPaddress of the IIP pool 610, such as a globally available IIP address.The appliance 200 may modify the packets transmitted from the client 102to have this mapped IP 640 when transmitted from the appliance 200 to aserver 106. Also, in some embodiments, the appliance 200 may modifypackets transmitted from the server 106 to the client 102 to change theMapped IP 640 to the IP address of the client 102, such as the IPaddress of the client 102 on the first network 104. In some embodiments,the appliance 200 stores in the IPLWDB 650 the association of the mappedIP 640 to the user and/or client 102.

In another embodiment, if the IIP policy 620 specifies to use a transfersession 645 at step 725, then, at step 735, the appliance 200 initiatesa transfer of an active session of the user. In one embodiment, uponreceiving, by the appliance 200, a request from a first client operatedby a user to establish a VPN session, the appliance may create atemporary VPN session with the client. In some embodiments, theappliance 200 may refuse to accept any data received via the temporarysession until a new VPN session is created from temporary session. Inother embodiments, the temporary VPN session may be allocated lessresources by the appliance than would be allocated to a standard VPNsession. In another embodiment, a temporary VPN session may not beassigned an IIP address 282, or may otherwise be prevented fromreceiving data. In some embodiments, the appliance may identify a numberof properties associated with the existing session. In one embodiment,after identifying an existing session, the appliance 200 may transmit amessage to the user via the previously existing session indicating thecurrent session attempt.

In some embodiments, the appliance 200 may transmit to the client 102 ofthe user a request for information corresponding to whether to terminatethe previous session. In some embodiments, this request may comprise aweb page which accepts user input. For example, the web page maycomprise an enumerated list of existing sessions, with input means forthe user to a select one or more sessions to be terminated. In otherembodiments, this request may comprise a communication to a client agent120, which then may respond on behalf of the user. In some embodiments,this request may comprise a request for information corresponding towhether to terminate one or more of a plurality of previous sessions.

In one embodiment, the request may comprise information relating to anyof the properties of the existing session. In some embodiments, thisinformation may be displayed to the user along with the choice ofwhether to terminate the existing session. For example, a web page maybe displayed to the user stating “you have a previously existing sessionwhich was opened July 2nd at 10:30 am, do you wish to close?” In otherembodiments, this information may be transmitted to a client agent whichmay then make a determination whether to close a previously existingsession based on the properties of the previously existing session. Forexample, a client agent 120 executing on the client making the newsession request may determine to automatically terminate a previoussession in the event that no applications are currently associated withthe previous session.

In some embodiments, the request may also comprise a request forinformation relating to whether the user would like to transfer datafrom a previous session to a current session. For example, if a user wasremotely executing an application, the user may wish to resume theremote execution and the previous session or sessions associated withthe remote execution using the current session. After transmitting, fromthe appliance 200 to the client 102, a request for informationcorresponding to whether to terminate the previous session the appliancemay receive, from the client or the user, a response comprising anindication to terminate the previous session. In still otherembodiments, the appliance 200 may receive a response comprising arequest to transfer data associated with a previous session to thecurrent session. In these embodiments, the appliance 200 assigns the IIPaddress 282A of the previous session to the new session.

In the event the appliance 200 receives a response comprising anindication not to terminate the previous session, the appliance 200 mayrefuse to allow the user access, and terminate the temporary VPNsession. In these embodiments, the appliance 200 maintains theassociation of the IIP addresses 282 with the previous session and doesnot assign the IIP address to the new session. In other embodiments, theappliance 200 may create a new VPN session unrelated to any of theidentified previous sessions. In these embodiments, the appliance 200may assign an available IIP address from another entity, such as group,vServer or global or another user, to the new VPN session.

D. IIP Address Spoofing of an Application

Referring now to FIG. 8, an embodiment of steps of a method 800 forproviding an IIP address 282 to a request of an application for thelocal IP address of a client 102 is depicted. In one embodiment, themethod 800 is practiced is referred to as IIP “spoofing” of the client'sIP address. In some embodiments, spoofing is a situation in which aprogram successfully masquerades as another by changing data to make itlook, feel and/or act as another program but with the changed data. Asdescribed herein, the client agent 120 spoofs the local IP address ofthe client 102 on a first network 104 to be the IIP address 282 of theclient 102 or user on the second network 104′ or the network 104′accessed by the client via a VPN connection to the appliance 200. Withthe techniques depicted by method 800, the application receives inresponse to a request, the IIP address 282 of the client 102 on thesecond network 104′ instead of the local IP address on the network stack310. In some embodiments, the method 800 enables applications totransparently and seamlessly communicate to other applications via theSSL VPN connected network 104′ without changes or modification In oneembodiment, this technique is useful for online collaboration tools,such as NetMeeting, when the client or user establishes an SSL VPNconnection and needs to collaborate with other computers on the network104′ or other SSL VPN connected clients 102.

In brief overview of method 800, at step 805, the client 102 on a firstnetwork 104 establishes a connection via the appliance 200 to a secondnetwork 104′, such as an SSL VPN connection. At step 810, the appliance200 provides or assigns an IIP address on the second network 104′ forthe client 102. At step 815, an application on the client 102 requests anetwork identifier of the client 102. At step 820, the client agent 120determines the IIP address 282 of the client 102 on the second network104′. At step 825, in response to the request, the client agent 120provides the application the IIP address 282 of the second network 104′instead of the local IP address of the client 102 on the first network104.

In further details, at step 805, the client agent 102 establishes atransport layer connection with the appliance 200, such as via thetransport control protocol or user datagram protocol. In one embodiment,the client agent 120 establishes a tunnel connection with the appliance200 using any type and form of tunneling protocol. In anotherembodiment, the client agent 120 establishes a virtual private networkconnection via the appliance 200 to a network 104′. For example, theclient agent 120 may establish a virtual private network connection withthe appliance 200 to connect the client 102 on the first network 104 toa second network 104′. In some embodiments, the client agent 120establishes a SSL VPN connection with the appliance 200. In yet anotherembodiment, the client agent 120 establishes a tunnel or virtual privatenetwork connection using Transport Layer Secure (TLS) protocol. In oneembodiment, the client agent 120 establishes a tunnel connection withthe appliance 200 using the Common Gateway Protocol (CGP) manufacturedby Citrix Systems, Inc. of Ft. Lauderdale, Fla.

At step 810, the appliance 200 provides the client 102 an IP address onthe second network 104′. In one embodiment, the appliance 200 assignsthe client 102 an IIP address 282. In some embodiments, the appliance200 assigns the user of the client 102 an IIP address 282 using any ofthe techniques and methods discussed above in connection with method 700and FIG. 7. In another embodiment, the appliance 200 uses a Mapped IP640 address for the client 102. In yet another embodiment, the appliance200 and client 102 use a transferred session with its corresponding IIPaddress 282 for establishing the connection at step 805 and providingthe IIP address 282 at step 810. In some embodiments, the appliance 200,on behalf of the client 102, hosts the IIP address 282 of the client 102on network 104′.

At step 815, an application on the client 102 makes a request todetermine the IP address of the client 102. In some embodiments, theapplication makes any socket based application programming interface(API) calls to request the IP address of the client based on the hostname of the client 102. In one embodiment, the hooking mechanism 350intercepts the API call. In some embodiments, the hooking mechanism 350may intercept or hook any of the following function calls or messages ofan application: gethostbyname, getaddrinfo, and getsockname. In otherembodiments, the hooking mechanism 350 may hook any of the WindowsSocket API extensions such as WSAIoctl, WSALookupServiceBegin,WSALookupServiceNext, and WSALookupServiceEnd. In one embodiment,without hooking these API calls via the hooking mechanism 350, theapplication would receive from the network stack 310 the local IPaddress of the client 102 on the first network 104.

At step 820, the client agent 120 and/or hooking mechanism 820determines the IIP address 282 to return to the hooked API call. In oneembodiment, the hooking mechanism 350 responds with the IIP address 282assigned to the user. In another embodiment, the hooking mechanism 350responds with the IIP address 282 assigned to the client 102. In otherembodiments, the hooking mechanism 350 responds with the Mapped IPaddress 640 of the client 102 on the second network 104′. In yet anotherembodiment, the hooking mechanism 350 responds with the IP address onthe second network 104′ hosted by the appliance 200 on behalf of theclient 102.

In some embodiments, the client agent 120 and/or hooking mechanism 350transmits a request to the appliance 200 to determine the IIP address282 of the client 102. For example, the appliance 200 may query a tableor database, such as a the IPLWDB 650 to determine the IIP addressassociated with either the local client IP address, the user or theclient agent 120. In another embodiment, the client agent 120 performs aping command to determine the IIP address 282 associated with the useras will be described in further detail below in conjunction with FIG. 7.In some embodiments, the client agent 120 transmits a DNS query to theDNS 286 of the appliance 200 or another DNS server 606 to resolve theuser domain name 637 into an IIP address 282. In yet another embodiment,the client agent 120 stores or caches the IIP address 282 assigned tothe client or user from the appliance 200. In these embodiments, theclient agent 120 and/or hooking mechanism 350 can retrieve the IIPaddress 282 from local storage without making a request to the appliance200.

At step 825, the hooking mechanism 350 provides the IIP address 282determined at step 820 to the application in response to theapplication's request at step 815. In one embodiment, the hookingmechanism 350 provides a reply to the hooked function or API call. Inother embodiments, the hooking mechanism 350 provides a message to theAPI call. In some embodiments, the application continues operations withthe provided IIP address 282. For example, the application may transmitthe IIP address 282 to another client or application, such as via thepayload of a transport layer packet communicated via the VPN connection.In yet other embodiments, the applications uses the IIP address 282 inother socket-based API calls as if were the local IP address of theclient 102. In this manner, the application operates for the SSL VPNconnected network 104's without modification as if were communicating onthe first network 104′. With the techniques illustrated by theembodiment of method 800, the user, client 102 and application, such asan online collaboration tool, obtain the security and access controlbenefits and other functionality provided by the appliance in a seamlessand transparent manner.

E. IIP Address Querying of a User

Referring now to FIG. 9, an embodiment of steps of a method 900 forquerying the IIP address 282 of a user using a user domain name 637 isdepicted. In one embodiment, the method 900 is practiced in order foruser, client or application to determine the IIP address assigned to aSSL VPN user. In some embodiments, a naming scheme for the user domainnames 637 can be configured of the appliance 200. For example, a userdomain name policy 620 can specify the domain suffix 635 to be appendedto a user identifier. In this manner, a user understanding the userdomain naming scheme can easily and efficiently ping or DNS query theIIP address of an SSL VPN user on a network 104′. For example, the usermay ping the user domain name 637 of “<user id>.<mycompanyname.com>” todetermine the IIP address 282 assigned by the appliance 200 to the useror client of the user. In this manner, SSL VPN users can quicklydetermine the IIP addresses of other users when using collaborationtools, such as establishing a NetMeeting session between SSL VPN users.

In brief overview of method 900, at step 905, the client 102 on a firstnetwork 104 establishes a connection via the appliance 200 to a secondnetwork 104′, such as an SSL VPN connection. At step 910, the appliance200 provides or assigns an IIP address on the second network 104′ forthe client 102, and generates a user domain name 637 according to theuser domain name policy 630. At step 915, the appliance 200 stores theuser domain name 637 and IIP address association of the user in a DNS orDNS cache. At step 920, the appliance 200 receives a request for the IIPaddress 282 of the user based on the user domain name 637, such as via aping command or a DNS query. At step 925, the appliance determines fromthe domain name service, the IIP address 282 associated with the userdomain name 637. At step 730, the appliance 200 provides the determinedIIP address 282 of the user in response to the request.

In further details, at step 905, the client agent 102 establishes atransport layer connection with the appliance 200, such as via thetransport control protocol or user datagram protocol. In one embodiment,the client agent 120 establishes a tunnel connection with the appliance200 using any type and form of tunneling protocol. In anotherembodiment, the client agent 120 establishes a virtual private networkconnection via the appliance 200 to a network 104′. For example, theclient agent 120 may establish a virtual private network connection withthe appliance 200 to connect the client 102 on the first network 104 toa second network 104′. In some embodiments, the client agent 120establishes a SSL VPN connection with the appliance 200. In yet anotherembodiment, the client agent 120 establishes a tunnel or virtual privatenetwork connection using Transport Layer Secure (TLS) protocol. In oneembodiment, the client agent 120 establishes a tunnel connection withthe appliance 200 using the Common Gateway Protocol (CGP) manufacturedby Citrix Systems, Inc. of Ft. Lauderdale, Fla.

At step 910, the appliance 200 provides the client 102 an IP address onthe second network 104′. In one embodiment, the appliance 200 assignsthe client 102 an IIP address 282. In some embodiments, the appliance200 assigns the user of the client 102 an IIP address 282 using any ofthe techniques and methods discussed above in connection with method 700and FIG. 7 or method 800 and FIG. 8. In another embodiment, theappliance 200 uses a Mapped IP 640 address for the client 102. In yetanother embodiment, the appliance 200 and client 102 use a transferredsession with its corresponding IIP address 282 for establishing theconnection at step 805 and providing the IIP address 282 at step 810. Insome embodiments, the appliance 200, on behalf of the client 102, hoststhe IIP address 282 of the client 102 on network 104′.

At step 910, the appliance 200, in some embodiments, generates a userdomain name 637 based on the user domain name policy 630. For example,in one embodiment, the appliance 200 generates a user domain namecomprising a specified domain suffix 635 associated with the useridentifier. In one embodiment, the domain suffix 635 comprises a domainname of the network 104′ or the host name of the appliance 200. In someembodiments, any arbitrary domain suffix 635 may be specified for theuser domain name 637. In other embodiments, the appliance 200 has ormaintains an established user domain name 637 for the user. For example,the appliance 200 may re-associate a newly assigned IIP address 282 withthe user domain name 637.

At step 915, the appliance 200 stores in a domain name service or otherdatabase, the association of the IIP address 282 of the user with theuser domain name 637. In some embodiments, the appliance 200 stores arecord in the DNS that maps the IIP address 282 to the user domain name637. In one embodiment, the appliance 200 stores this record orassociation in the DNS 286 or DNS cache of the appliance. In otherembodiments, the appliance 200 stores a record mapping the IIP addressto the user domain name in another DNS, such as DNS 606. In yet anotherembodiment, the appliance 200 stores the IIP address/user domain name asa record or entry in the IPLWDB 650. In still other embodiments, theappliance 200 maintains the IIP address/user domain name association inmemory, such as in a data structure or object, or in storage, such as ina file or cache.

At step 920, the appliance 200 receives or intercepts a request todetermine the IIP address 282 of a user domain name 237. In someembodiments, the appliance 200 receives a DNS query to resolve the userdomain name 237 via an SSL VPN connection client. In other embodiments,200 receives he DNS query from any client 102 on the same 104′ ordifferent network 104 that can access the DNS 286 services of theappliance 200. In some embodiments, the appliance 200 receives the DNSquery forwarded from a server 106, another DNS, or another appliance200. In another embodiment, the appliance 200 intercepts any type andform of Internet Control Message Protocol (ICMP) request, such as a pingcommand, that refers to or includes the user domain name 237. In yetanother embodiment, the client agent 120 intercepts the ICMP request andtransmits the request to the appliance 200, such as via the SSL VPNconnection of the client or a control connection between the clientagent 120 and the appliance 200.

At step 925, the appliance 200 determines the IIP address 282 associatedwith the user domain name 638 specified via the request. In oneembodiment, the appliance 200 performs a lookup in the DNS cache 286. Inother embodiments, the appliance 200 transmits a DNS query request orlookup to another DNS, such as DNS 606. In some embodiments, theapplication 200 does a lookup in a database using the user domain name637 as the key or index. In yet another embodiment, the application 200performs a lookup operation in the IPLWDB 650 for the IIP address 282associated with the user domain name 637. In some embodiments, theapplication 200 looks up the IIP address 282 in memory, such as via adata structure or object. In other embodiments, the application 200determines the IIP address 282 from a cache. In still anotherembodiment, the appliance 200 determines the IIP address 282 from aclient agent 120, for example, the client agent 120 providing the SSLVPN connection of the user identified by the user domain name 237.

At step 930, the appliance 200 provides the determined IIP address 282of the user in response to the request of step 920. In some embodiments,the appliance 200 transmits a response to the sender of the DNS query.For example, the appliance 200 may transmit the DNS query response to aclient, server, another appliance or another DNS. In other embodiments,the appliance 200 transmits a message to a client agent 120 identifyingthe IIP address 282. For example, in the case of the client agent 120intercepting a ping of an SSL VPN user, the client agent 120 responds tothe ping with the IIP address of the user domain name. In someembodiments, the client agent 120 also provides ping statistics alongwith the IIP address 282, which may have been determined and provided bythe appliance 200. With the IIP address of the SSL VPN user, a user,client or application can communicate, collaborate or connect to theidentified SSL VPN user.

In view of the structure, functions and operations of the system andmethods described above, the appliance and client agent providetechniques for more efficiently using assigned Intranet InternetProtocol (IIP) addresses by SSL VPN users. The appliance manages andsupports IIP stickiness to a user by assigning an IIP address based onpolicy, temporal and status information. With the configurable userdomain naming scheme, the appliances provides a mechanism for users,clients and other applications to determine the IIP address assigned toa SSL VPN user. Additionally, the client agent provides a mechanism forseamlessly providing the IIP address to applications communicating viaan SSL VPN connection to the private network.

G. Multi-Core System Providing an HP addressing Environment

In SSL VPN, any session may be assigned an Intranet IP(IIP), forexample, as described in any of the above embodiments. This IIP addressmay be used for all outgoing traffic for that session. In someembodiments, this IIP may accept incoming packets, which are forwardedto the client over a control channel, such as to the client agent.

IIPs may be associated with users, groups or vservers throughconfiguration. When the sessions are created with any of these entities,the IIP associated with these entities may be allocated to the session.When the session terminates, this IIP may be deallocated and returnedback to an IIP pool. If there are no IIPs to allocate, then the user maybe given the option to transfer the login, e.g., terminate anotherexisting session of the user and take over that IIP.

In a multi-core system, multiple packet engines across correspondingcores may be working concurrently processing data packets from dataflows of SSL VPN sessions. For example, a first core may establish a SSLVPN session with a client. Any one of the other cores, such as a secondcore, may received packets related to the session owned by the firstcore. Embodiments of the systems and method described below providemanagement of IIP addresses for the multi-core/multi-packet engineapproach to providing SSL VPN service. In some embodiments, the approachto managing IIP addresses is to have one packet engine on a core act asa master or controller of the IIPs for the remaining packet engines andcores. The packet engines/cores use a protocol for communicationsregarding IIP management.

Referring now to FIG. 10A, an embodiment of a multi-core system with IIPmanagement across the plurality of cores is depicted. In brief overview,In brief overview, the multi-core system may include a plurality ofcores 505A-505N (generally referred to as 505), such as core 1 505Athrough core N 505N. Each of the cores 505A-505N may include or executea packet engine 584A-548N (generally referred to as 548). The cores maycommunicate with each other via any core to core interface orcommunication mechanism described herein. One or more of the cores mayinclude and/or be designated an IIP controller 1010. The controllerdesignation 1018 may be communicated to the other cores via anycore-to-core interface. A plurality of the cores may include an IIPinterface 1010B-1010N to interface or communicate with the IIPcontroller. The IIP controllers and IIP interfaces may use an IIPprotocol 1005 to communicate, such as to manage IIP addresses in thesystem. For example, the protocol 1005 may include a request for IIP1020 with a response of IIP(s) 1021. The protocol 1005 may include atransfer login request 1022 with a response 1023 and a logout request1024 and response 1025.

In view of the communications and scenarios described in connection withIIP management of FIGS. 6-9, any such communication may be received on acore different than the core receiving and/or establishing the SSL VPNconnection or connection request. For example, the SSL VPN connectionrequest may be received on one core, such as core 6, while a client'sset client request is received on core 2. The IIP controller and IIPinterfaces may be used to communicate between cores information aboutIIP addresses.

In further details, the multi-core system may be any of the embodimentsof the system 545 described in connection with FIG. 5A and embodimentsdescribed elsewhere herein. As such, the multi-core system may be amulti-core device between a plurality of clients and a plurality ofservice. The multi-core device may provide to the plurality of clientsVPN access, such as SSL VPN access, to the plurality of servers. Theclients may be on one or more networks, such as public networks,different from the private or internal network of the plurality ofservers. Each packet engine on corresponding cores may each provide SSLVPN 280 functionality, such as an SSL VPN session. With the flow baseddata parallelism scenario 520, each packet engine/core may receivepackets for a data flow assigned to another core. As such, a packetengine/core may receive packets of a SSL VPN session managed or assignedto another core.

The multi-core system may designate or assign any one of the cores asthe IIP controller. The multi-core system may design a first core as aprimary IIP controller and a second core as a backup IIP controller. Thedesignation of the one or more cores as an IIP controller may be donevia configuration. In some embodiments, any operating system of thedevice may be designed and constructed to select one or more of thecores as the IIP controller.

The IIP controller 1010 may comprise hardware and/or software executingon a device, such as a device of the multi-core system. The IIPcontroller 1010 may comprise an application, a program, a service, aprocess, a task or any type and form of executable instructions. The IIPcontroller 1010 may execute and operate in kernel mode. The IIPcontroller 1010 may execute and operate in user mode. Portions of theIIP controller 1010 may execute and/or operate in any combination ofuser mode and kernel mode. In some embodiments, the IIP controller 1010may be part of the packet engine. In some embodiments, the IIPcontroller 1010 is in communication with the packet engine. In someembodiments, the IIP controller 1010 may interface or be integrated withthe packet engine.

The IIP controller may comprise logic, operations and functions toprovide IIP address management and coordination among the cores andpacket engine thereon, such as for any of the operations and methoddescribed herein. The IIP controller may control and coordinate theassignment of IIP addresses, such as the IIP assignment described inconnection with any of the FIGS. 6-9. The IIP controller may control andcoordinate the assignment of IIP address pools, such as any of thosepools described herein. The IIP controller may establish, coordinate,manage and/or track the IIP address for any session managed by ortraversing the multi-core system, such as any SSL VPN sessionestablished or managed by any core.

The IIP controller may provide any type and form of interface forreceiving communications from a core, packet engine and/or a IIPinterface 1015B-N. The IIP controller may use any of the core-to-coreinterfaces to communicate with another core, packet engine and/or IIPinterface 1015. The IIP controller may receive communications, such asrequests or messages, from any of the IIP interfaces operating on othercores. The IIP controller may transmits communications, such asresponses or messages, to any of the IIP interfaces operating on othercores.

The IIP interface 1015 may comprise hardware and/or software executingon a device, such as a device of the multi-core system. The IIPinterface 1015 may comprise an application, a program, a service, aprocess, a task or any type and form of executable instructions. The IIPinterface 1015 may execute and operate in kernel mode. The IIP interface1015 may execute and operate in user mode. Portions of the IIP interface1015 may execute and/or operate in any combination of user mode andkernel mode. In some embodiments, the IIP interface 1015 may be part ofthe packet engine. In some embodiments, the IIP interface 1015 is incommunication with the packet engine. In some embodiments, the IIPinterface 1015 may interface or be integrated with the packet engine.

The IIP interface 1015 may comprise logic, operations and functions tocommunicate with the IIP controller for obtaining IIP addresses,managing IIP addresses and/or providing information about sessions. TheIIP interface may transmits communications, such as request or messages,to an IIP controller operating on a core. The IIP interface may receivecommunications, such as responses or messages, from an IIP controlleroperating on a cores.

The IIP controller and IIP interface may use a protocol forcommunicating messages. The protocol may be constructed in any form andformat, such as a request and response protocol with any type of fields,headers and/or payloads. The protocol may carry request for information,instructions or other information used in the management of IIPaddresses. The protocol may carry responses providing IIP addressinformation and/or instructions on the use and management of IIPaddresses.

In some embodiments, the protocol may include a request 1020 for an IIPaddress. In some embodiments, the request includes session information,such a SSL VPN session information. In some embodiments, the requestormarshals the session information and sends the marshaled sessioninformation with or as part of the request. In some embodiments, theprotocol includes a response 1021 to the request identifying orproviding one or more IIP addresses. In some embodiments, the responseincludes a list of IIP addresses. In some embodiments, the responseincludes an identification that an IIP address is not available for thesession. In some embodiments, the response includes an identification ofanother session, user or entity with an IIP address.

In some embodiments, a core, such as core 2, may receive a setclientmessage 1030 from the client agent. The setclient message may identifythe type of client or client agent running on the client device. Forexample, the client may be of type CPNV or Native. Core 2 may not be theowner core of the session. Core 2 may inform the owner core of the eventand wait for a response. The session owner core may in turn request 1020the IIP Controller for the IIP addresses. In the message to the IIPController, the session may also be marshaled and sent with or inassociation with the request. The IIP controller then looks at theuser/group/vserver entities in session and tried to pick an IIP address.If an IIP is available, the IIP controller sends a response 1021 to thesession owner about the IIP. The session owner in turn may inform thecore and packet engine which received the setclient message 1020. TheIIP controller, session owner core or the core receiving the message mainformation any or all of the other packet engines/cores about the IIPallocation. For example, the IIP controller may broadcast the IIPallocation via core-to-core messages. The packet engines upon the IIPallocation, or notice of the same, may start accepting incoming packetson that IIP.

If an IIP is not available, the IIP controller may send a response tothe owner core to provide or identify a list of existing allocated IIPsfor the user corresponding to the current session. The owner core may inturn inform the packet engine/core which received the setclient request.This packet engine/core may then reply back to the client with theTransfer Login dialogue.

In some embodiments, the protocol may include a request 1022 to transferlogin For example, if at the time of setclient a Transfer Client isreturned to the client, and the client issues a “Transfer ClientRequest”, then the owner core is informed about this from the receivingcore. The owner core transmits the request to transfer login to the IIPController. The request 1022 may include information about the client,the user, the session and/or the IIP address of the session. The IIPController transfers the session to the IIP address and send theresponse 1023 to the owner core. This response may then be sent back tothe packet engine/core which got the request. The response may includeinformation identifying or providing the transfer of allocation of theIIP address to the session.

In some embodiments, the protocol may include a request 1024 for logoutor upon a user logging out. For example, upon logout, the owner core mayreceive information about the logout from the receiving core. The ownercore may send the request 1024 to inform the IIP Controller todeallocate the IIP address. In some embodiments, the IIP controller mayprovide a response 1025 confirming or identifying the deallocation ofthe IIP address. In some embodiments, the response may be provided toall the cores. In some embodiments, the owner core broadcasts thedeallocation of the IIP address to the other cores. In some embodiments,the receiving core broadcasts the deallocation of the IIP address to theother cores. In some embodiments, the IIP controller broadcasts thedeallocation of the IIP address to the other cores. Upon notice orreceipt of IIP address deallocation, each packet engine may stopaccepting packets on that IIP address.

Referring now to FIG. 10B, an embodiments of steps of a method 1050 forproviding IIP management in a multi-core system is depicted. In briefoverview, at step 1055, a core is designed as the IIP controller. Atstep 1060, a non-owner core of a session receives a client communicationin connection with the session, such as a set client message 1030. Atstep 1065, the non-owner core determines the owner core of the session,such as via the session identifier. At step 1070, the non-owner coresends a communication to the owner core about the session. At step 1075,the owner core communicates a request to the IIP controller via the IIPprotocol. At step 1080, the IIP controller communicates a response tothe owner core. At step 1085, the other cores are updated on themanagement of the IIP address(es).

In further details, at step 1055, In some embodiments, may designate acore to provide or establish the IIP controller. In some embodiments,the system selects or identifies a core from the plurality of cores. Insome embodiments, the multi-core system selects or identifies a basecore or a first core in the sequence of cores. In some embodiments, thecore or core number may be specified via configuration of the multi-coresystem. In some embodiments, the multi-core system allocates apredetermined core.

In some embodiments, the multi-core system designates or establishes theIIP controller upon initialization of the system. In some embodiments,the multi-core system designates or establishes the IIP controller uponrequest by a packet engine. In some embodiments, the multi-core systemdesignates or establishes the IIP controller upon initialization orstart up of a packet engine. In some embodiments, the multi-core systemdesignates or establishes the IIP controller upon a connection request.In some embodiments, the multi-core system designates or establishes theIIP controller upon request from a user, such as an administrator. Insome embodiments, the multi-core system designates or establishes theIIP controller upon a change in configuration or request to changeconfiguration of the system.

The designation of the IIP controller on a core may be communicated tothe other cores via a designation communication 1018. This communicationmay be via any type of core-to-core interface. The communication mayidentify a name or a number of the core on which the IIP controller isexecuting.

At step 1060, any core of the plurality of cores may receive any typeand form of client message 1030 in connection with a session. The corereceiving the client message may not be the core that established orowns the session. Any core may receive the client message. In someembodiments, the core receiving the client message may be the ownercore. The client message may be any type and form of message, such as aset client message. For example, during the establishing of an SSL VPNor VPN session with the client, the client and multi-core system mayexchange messages, such as via a packet engine and a client agent. Onany of these messages, the system may trigger the establishment orallocation of an IIP address for the session. In some embodiments, theclient message is a request for an address, such as an IIP address.

At step 1065, the non-owner core determines the owner core of thesession, such as via the session identifier. The non-owner core maydetermine the core that owns or manages the session via any type andform of hash of the session identifier. The result of the hash mayidentify the number or name of the owner core. The result of the hashmay provide an index into any type of lookup to identify the number orname of the owner core. The non-owner core may identify the owner corevia any mathematical operation, algorithm or function of the sessionidentifier. In some embodiments, the session identifier or any portionthereof is encoded with the identifier of the core that owns or managesthe session.

At step 1070, the non-owner core sends a communication to the owner coreabout the session. Upon determining the owner core, the non-owner coremay send a communication to the owner core regarding the client message.In some embodiments, the non-owner core sends a copy of the message tothe owner core. In some embodiments, the non-owner core identifies theevent of the client message and sends information about the event to theowner core. In some embodiments, the non-owner core sends to the ownercore information about the session. In some embodiments, the non-ownercore sends to the owner core a request for information about thesession. In some embodiments, the non-owner core sends to the owner corea request for an IIP address for the session. In some embodiments, thenon-owner core sends to the owner core a request to transfer a login. Insome embodiments, the non-owner core sends to the owner core a requestto logout of a session. In some embodiments, the communications includesa session identifier. In some embodiments, the communications includesmarshaled session information.

At step 1075, the owner core communicates a request to the IIPcontroller via the IIP protocol. In some embodiments, the IIP interfaceof the owner core communicates with the IIP controller. In someembodiments, the packet engine of the owner core communicates with theIIP controller. In some embodiments, the owner core sends any of therequest of the IIP protocol, such as request for IIP 1020, transferlogin request 1022 or logout request 1024. Responsive to the request,the IIP controller may perform any of the IIP address managementdescribed herein such as in conjunction with FIGS. 6-9. Responsive tothe request, the IIP controller may allocate an IIP address. Responsiveto the request, the IIP controller may deallocate an IIP address.Responsive to the request, the IIP controller may put an IIP addressback to a IIP address pool. Responsive to the request, the IIPcontroller may remove an IIP address from an IIP address pool.Responsive to the request, the IIP controller may move IIP addressbetween IIP address pool(s). Responsive to the request, the IIPcontroller may update a state or status of the IIP address. Responsiveto the request, the IIP controller may update a state or status of thesession.

At step 1080, the IIP controller communicates a response to the ownercore. In some embodiments, the IIP interface of the owner core receivesthe response from the IIP controller. In some embodiments, the packetengine of the non-owner core receives the response from the IIPcontroller. In some embodiments, the IIP controller core sends any ofthe responses of the IIP protocol, such as a response for IIP 1021,transfer login response 1023 or logout request 1025. In someembodiments, the IIP controller sends a response that acknowledgesreceipt of the request. In some embodiments, the IIP controller does notsend a response to the request.

At step 1085, the other cores are updated on the management of and/orchanges to the IIP address(es). In some embodiments, the IIP controllercommunicates updates to the core, packet engines and/or IIP interfacesabout the allocation or deallocation of an IIP address to a session. Insome embodiments, the IIP controller communicates updates to the core,packet engines and/or IIP interfaces about the transfer of an IIPaddress between sessions. In some embodiments, the IIP controllercommunicates the update via the IIP protocol. In some embodiments, theIIP controller communicates the update via a core-to-core interface. Insome embodiments, the IIP controller or core of the IIP controllerbroadcasts updates on the IIP addresses to the other core or IIPinterfaces. Responsive to an allocation of an IIP address, a packetengine on core may accept communications to or from the IIP address.Responsive to an allocation of an IIP address, each of the packetengines on each core may accept communications to or from the IIPaddress. Responsive to a de-allocation of an IIP address, a packetengine on a core may stop accepting communications to or from the IIPaddress. Responsive to a deallocation of an IIP address, each of thepacket engines on each core may stop accepting communications to or fromthe IIP address.

Many alterations and modifications may be made by those having ordinaryskill in the art without departing from the spirit and scope of theinvention. Therefore, it must be expressly understood that theillustrated embodiments have been shown only for the purposes of exampleand should not be taken as limiting the invention, which is defined bythe following claims. These claims are to be read as including what theyset forth literally and also those equivalent elements which areinsubstantially different, even though not identical in other respectsto what is shown and described in the above illustrations.

The invention claimed is:
 1. A method for managing intranet internetprotocol addresses via a device comprising a plurality of cores, themethod comprising: (a) establishing, on a device comprising a pluralityof cores, a controller for managing intranet internet protocol (IIP)addresses assigned to sessions of users; (b) receiving, by a controller,from a first core a request for an IIP address for a session of a user;(c) determining, by the controller that an IIP address is not availableto assign to the session; (d) communicating, by the controller to asecond core, a second request to identify one or more existing IIPaddresses allocated to the user; and (e) transferring, by thecontroller, from the one or more existing IIP addresses to the sessionof the request an existing IIP address allocated to the user.
 2. Themethod of claim 1, wherein step (a) further comprises establishing thecontroller on one of the first core or the second core of the pluralityof cores.
 3. The method of claim 1, wherein step (a) further comprisingselecting one core of the plurality of cores as the core to establishthe controller and communicating the selection to each of the otherscores of the plurality of cores.
 4. The method of claim 1, wherein step(b) further comprises transmitting, by the first core, the request forthe IIP address responsive to the client requesting to establish thesession via the device.
 5. The method of claim 1, wherein step (c)further comprises determining, by the controller, that the IIP addressesavailable to the user have been allocated.
 6. The method of claim 1,wherein step (d) further comprises determining, by the controller, thatthe second core is an owner of the session.
 7. The method of claim 1,wherein step (d) further comprises receiving, by the controller from thesecond core, the one or more existing IIP addresses allocated to theuser and corresponding session information.
 8. The method of claim 1,wherein step (e) further comprises receiving, by the controller, a thirdrequest to transfer login of an existing session of the user to thesession of the request, the second request comprising information aboutthe client, the user, the session and the IIP address.
 9. The method ofclaim 1, wherein step (e) further comprises transmitting, by the firstcore, a third request to the client to transfer login of an existingsession of the user to the session of the request.
 10. The method ofclaim 1, further comprises communicating, by the controller, to theplurality of cores, the transfer of the allocation of the IIP address tothe session.
 11. A system for managing intranet internet protocoladdresses via a device comprising a plurality of cores, the systemcomprising: a device comprising a plurality of cores; a controllerestablished on the device and configured to manage intranet internetprotocol (IIP) addresses assigned to sessions of users; wherein thecontroller is configured to receive from a first core a request for anIIP address for a session of a user, determine that an IIP address isnot available to assign to the session and communicate to a second core,a second request to identify one or more existing IIP addressesallocated to the user; and wherein the controller is configured totransfer from the one or more existing IIP addresses to the session ofthe request an existing IIP address allocated to the user.
 12. Thesystem of claim 11, wherein the controller is established on one of thefirst core or the second core of the plurality of cores.
 13. The systemof claim 11, wherein the device is configured to select one core of theplurality of cores as the core to establish the controller and theselected core is configured to communicate the selection to each of theothers cores of the plurality of cores.
 14. The system of claim 11,wherein the first core is further configured to communicate the requestfor the IIP address responsive to the client requesting to establish thesession via the device.
 15. The system of claim 11, wherein thecontroller is further configured to determine that the IIP addressesavailable to the user have been allocated.
 16. The system of claim 11,wherein the controller is further configured to determine that thesecond core is an owner of the session.
 17. The system of claim 11,wherein the controller is further configured to receive from the secondcore, the one or more existing IIP addresses allocated to the user andcorresponding session information.
 18. The system of claim 11, whereinthe controller is further configured to receive a third request totransfer login from an existing session of the user to the session ofthe request, the second request comprising information about the client,the user, the session and the IIP address.
 19. The system of claim 11,wherein the first core is further configured to communicate a thirdrequest to the client to transfer login from an existing session of theuser to the session of the request.
 20. The system of claim 11, whereinthe controller is further configured to communicate to the plurality ofcores the transfer of the allocation of the IIP address to the session.